diff --git a/.gitignore b/.gitignore
index df9d92d91..8ebe6699a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -288,3 +288,8 @@ sg_test.sh
 sg-sync-api-preview.md
 sg-sync-api-内部.md
 mdf_file_read_count.sh
+.dev-stack/
+
+# Local-only 门户联调 (do not commit)
+.cursor/rules/local-portal-dev-stack.mdc
+scripts/dev-stack.sh
diff --git a/src/backend/bisheng/knowledge/domain/repositories/implementations/knowledge_space_pin_repository_impl.py b/src/backend/bisheng/knowledge/domain/repositories/implementations/knowledge_space_pin_repository_impl.py
index 42a301e7c..b7ddaaa64 100644
--- a/src/backend/bisheng/knowledge/domain/repositories/implementations/knowledge_space_pin_repository_impl.py
+++ b/src/backend/bisheng/knowledge/domain/repositories/implementations/knowledge_space_pin_repository_impl.py
@@ -19,14 +19,20 @@ class KnowledgeSpacePinRepositoryImpl(BaseRepositoryImpl[UserLink, int], Knowled
     async def lock_user(self, user_id: int) -> None:
         await self.session.exec(select(_USER_TABLE.c.user_id).where(_USER_TABLE.c.user_id == user_id).with_for_update())
 
-    async def list_for_user(self, user_id: int) -> set[int]:
+    async def list_for_user(self, user_id: int) -> list[int]:
         result = await self.session.exec(
-            select(UserLink.type_detail).where(
+            select(UserLink.type_detail)
+            .where(
                 UserLink.user_id == user_id,
                 UserLink.type == KNOWLEDGE_SPACE_PIN_TYPE,
             )
+            .order_by(UserLink.create_time.desc(), UserLink.id.desc())
         )
-        return {int(type_detail) for type_detail in result.all() if str(type_detail).isdigit()}
+        ordered: list[int] = []
+        for type_detail in result.all():
+            if str(type_detail).isdigit():
+                ordered.append(int(type_detail))
+        return ordered
 
     async def add_pin(self, user_id: int, space_id: int) -> bool:
         existing = await self.session.exec(
diff --git a/src/backend/bisheng/knowledge/domain/repositories/interfaces/knowledge_space_pin_repository.py b/src/backend/bisheng/knowledge/domain/repositories/interfaces/knowledge_space_pin_repository.py
index a02bdf714..6b6c7ee3f 100644
--- a/src/backend/bisheng/knowledge/domain/repositories/interfaces/knowledge_space_pin_repository.py
+++ b/src/backend/bisheng/knowledge/domain/repositories/interfaces/knowledge_space_pin_repository.py
@@ -9,7 +9,8 @@ class KnowledgeSpacePinRepository(BaseRepository[Any, int], ABC):
     async def lock_user(self, user_id: int) -> None: ...
 
     @abstractmethod
-    async def list_for_user(self, user_id: int) -> set[int]: ...
+    async def list_for_user(self, user_id: int) -> list[int]:
+        """Return pinned space ids ordered by create_time DESC (most recent first)."""
 
     @abstractmethod
     async def add_pin(self, user_id: int, space_id: int) -> bool: ...
diff --git a/src/backend/bisheng/knowledge/domain/services/knowledge_space_pin_service.py b/src/backend/bisheng/knowledge/domain/services/knowledge_space_pin_service.py
index 47727071c..41a975d28 100644
--- a/src/backend/bisheng/knowledge/domain/services/knowledge_space_pin_service.py
+++ b/src/backend/bisheng/knowledge/domain/services/knowledge_space_pin_service.py
@@ -13,12 +13,17 @@ MAX_PINS_PER_LEVEL = 5
 
 class KnowledgeSpacePinService:
     @staticmethod
-    async def get_pinned_space_ids(user_id: int, visible_space_ids: set[int]) -> set[int]:
+    async def list_pinned_space_ids(user_id: int, visible_space_ids: set[int]) -> list[int]:
+        """Pinned space ids visible to the user, most recently pinned first."""
         if not visible_space_ids:
-            return set()
+            return []
         async with get_async_db_session() as session:
             pinned_ids = await KnowledgeSpacePinRepositoryImpl(session).list_for_user(user_id)
-        return pinned_ids & visible_space_ids
+        return [space_id for space_id in pinned_ids if space_id in visible_space_ids]
+
+    @staticmethod
+    async def get_pinned_space_ids(user_id: int, visible_space_ids: set[int]) -> set[int]:
+        return set(await KnowledgeSpacePinService.list_pinned_space_ids(user_id, visible_space_ids))
 
     @classmethod
     async def set_pin(
@@ -33,7 +38,7 @@ class KnowledgeSpacePinService:
             repository = KnowledgeSpacePinRepositoryImpl(session)
             await repository.lock_user(user_id)
             pinned_ids = await repository.list_for_user(user_id)
-            current_ids = pinned_ids & visible_space_ids
+            current_ids = [item for item in pinned_ids if item in visible_space_ids]
             if not is_pinned:
                 await repository.remove_pin(user_id, space_id)
                 await session.commit()
@@ -55,19 +60,21 @@ class KnowledgeSpacePinService:
             for item in spaces
             if (item.get("id") if isinstance(item, dict) else getattr(item, "id", None)) is not None
         }
-        pinned_ids = await cls.get_pinned_space_ids(user_id, visible_ids)
+        pinned_order = await cls.list_pinned_space_ids(user_id, visible_ids)
+        pin_rank = {space_id: index for index, space_id in enumerate(pinned_order)}
         pinned: list[Any] = []
         normal: list[Any] = []
         for item in spaces:
             item_id = int(item.get("id") if isinstance(item, dict) else item.id)
             level = item.get("space_level") if isinstance(item, dict) else getattr(item, "space_level", None)
             level_value = getattr(level, "value", level)
-            is_pinned = level_value != KnowledgeSpaceLevelEnum.PERSONAL.value and item_id in pinned_ids
+            is_pinned = level_value != KnowledgeSpaceLevelEnum.PERSONAL.value and item_id in pin_rank
             if isinstance(item, dict):
                 item["is_pinned"] = is_pinned
             else:
                 item.is_pinned = is_pinned
             (pinned if is_pinned else normal).append(item)
+        pinned.sort(key=lambda item: pin_rank[int(item.get("id") if isinstance(item, dict) else item.id)])
         return pinned + normal
 
     @staticmethod
diff --git a/src/backend/test/knowledge/test_knowledge_space_pin_lists.py b/src/backend/test/knowledge/test_knowledge_space_pin_lists.py
index 1a5b57996..05f18f176 100644
--- a/src/backend/test/knowledge/test_knowledge_space_pin_lists.py
+++ b/src/backend/test/knowledge/test_knowledge_space_pin_lists.py
@@ -42,14 +42,14 @@ async def test_stale_cached_pin_is_reset_before_return():
         ),
         patch.object(
             KnowledgeSpacePinService,
-            "get_pinned_space_ids",
-            new=AsyncMock(return_value=set()),
-        ) as get_pins,
+            "list_pinned_space_ids",
+            new=AsyncMock(return_value=[]),
+        ) as list_pins,
     ):
         result = await service._list_accessible_spaces()
 
     assert result[0].is_pinned is False
-    get_pins.assert_awaited_once_with(7, {10})
+    list_pins.assert_awaited_once_with(7, {10})
 
 
 @pytest.mark.asyncio
@@ -63,8 +63,8 @@ async def test_personal_residual_link_never_marks_list_item_pinned():
     ]
     with patch.object(
         KnowledgeSpacePinService,
-        "get_pinned_space_ids",
-        new=AsyncMock(return_value={10}),
+        "list_pinned_space_ids",
+        new=AsyncMock(return_value=[10]),
     ):
         result = await KnowledgeSpacePinService.apply_pins(spaces, user_id=7)
 
diff --git a/src/backend/test/knowledge/test_knowledge_space_pin_repository.py b/src/backend/test/knowledge/test_knowledge_space_pin_repository.py
index 293c61d3d..81f1f9fbd 100644
--- a/src/backend/test/knowledge/test_knowledge_space_pin_repository.py
+++ b/src/backend/test/knowledge/test_knowledge_space_pin_repository.py
@@ -1,3 +1,4 @@
+from datetime import datetime, timedelta
 from unittest.mock import AsyncMock
 
 import pytest
@@ -34,11 +35,42 @@ async def test_list_add_and_remove_are_scoped_and_idempotent(session: AsyncSessi
 
     assert await repository.add_pin(1, 10) is True
     assert await repository.add_pin(1, 10) is False
-    assert await repository.list_for_user(1) == {10}
+    assert await repository.list_for_user(1) == [10]
 
     assert await repository.remove_pin(1, 999) is False
     assert await repository.remove_pin(1, 10) is True
-    assert await repository.list_for_user(1) == set()
+    assert await repository.list_for_user(1) == []
+
+
+@pytest.mark.asyncio
+async def test_list_for_user_orders_by_create_time_desc(session: AsyncSession):
+    repository = KnowledgeSpacePinRepositoryImpl(session)
+    now = datetime.now()
+    session.add_all(
+        [
+            UserLink(
+                user_id=1,
+                type="knowledge_space_pin",
+                type_detail="10",
+                create_time=now - timedelta(minutes=2),
+            ),
+            UserLink(
+                user_id=1,
+                type="knowledge_space_pin",
+                type_detail="11",
+                create_time=now - timedelta(minutes=1),
+            ),
+            UserLink(
+                user_id=1,
+                type="knowledge_space_pin",
+                type_detail="12",
+                create_time=now,
+            ),
+        ]
+    )
+    await session.commit()
+
+    assert await repository.list_for_user(1) == [12, 11, 10]
 
 
 @pytest.mark.asyncio
diff --git a/src/backend/test/knowledge/test_knowledge_space_pin_service.py b/src/backend/test/knowledge/test_knowledge_space_pin_service.py
index 13c0f1a88..514f064ab 100644
--- a/src/backend/test/knowledge/test_knowledge_space_pin_service.py
+++ b/src/backend/test/knowledge/test_knowledge_space_pin_service.py
@@ -10,7 +10,8 @@ from bisheng.knowledge.domain.services.knowledge_space_pin_service import Knowle
 
 
 @pytest.mark.asyncio
-async def test_apply_pins_intersects_visible_ids_forces_personal_false_and_keeps_stable_order():
+async def test_apply_pins_orders_by_pin_recency_and_forces_personal_false():
+    # Input list order is 1,2,3,4 but pin order is newest-first: 4 then 2.
     spaces = [
         SimpleNamespace(id=1, space_level=KnowledgeSpaceLevelEnum.PUBLIC, is_pinned=False),
         SimpleNamespace(id=2, space_level=KnowledgeSpaceLevelEnum.PUBLIC, is_pinned=False),
@@ -19,13 +20,13 @@ async def test_apply_pins_intersects_visible_ids_forces_personal_false_and_keeps
     ]
     with patch.object(
         KnowledgeSpacePinService,
-        "get_pinned_space_ids",
-        new=AsyncMock(return_value={2, 3, 4, 999}),
-    ) as get_pins:
+        "list_pinned_space_ids",
+        new=AsyncMock(return_value=[4, 2, 3, 999]),
+    ) as list_pins:
         result = await KnowledgeSpacePinService.apply_pins(spaces, user_id=7)
 
-    get_pins.assert_awaited_once_with(7, {1, 2, 3, 4})
-    assert [item.id for item in result] == [2, 4, 1, 3]
+    list_pins.assert_awaited_once_with(7, {1, 2, 3, 4})
+    assert [item.id for item in result] == [4, 2, 1, 3]
     assert [item.is_pinned for item in result] == [True, True, False, False]
 
 
@@ -37,8 +38,8 @@ async def test_apply_pins_supports_public_list_dicts():
     ]
     with patch.object(
         KnowledgeSpacePinService,
-        "get_pinned_space_ids",
-        new=AsyncMock(return_value={2}),
+        "list_pinned_space_ids",
+        new=AsyncMock(return_value=[2]),
     ):
         result = await KnowledgeSpacePinService.apply_pins(spaces, user_id=7)
 
@@ -46,11 +47,35 @@ async def test_apply_pins_supports_public_list_dicts():
     assert [item["is_pinned"] for item in result] == [True, False]
 
 
+@pytest.mark.asyncio
+async def test_apply_pins_re_pin_moves_space_to_front():
+    """Pin A then B → [B, A]; unpin A and re-pin A → [A, B]."""
+    spaces = [
+        SimpleNamespace(id=1, space_level=KnowledgeSpaceLevelEnum.PUBLIC, is_pinned=False),
+        SimpleNamespace(id=2, space_level=KnowledgeSpaceLevelEnum.PUBLIC, is_pinned=False),
+    ]
+    with patch.object(
+        KnowledgeSpacePinService,
+        "list_pinned_space_ids",
+        new=AsyncMock(return_value=[2, 1]),
+    ):
+        after_pin_b = await KnowledgeSpacePinService.apply_pins(spaces, user_id=7)
+    assert [item.id for item in after_pin_b] == [2, 1]
+
+    with patch.object(
+        KnowledgeSpacePinService,
+        "list_pinned_space_ids",
+        new=AsyncMock(return_value=[1, 2]),
+    ):
+        after_re_pin_a = await KnowledgeSpacePinService.apply_pins(spaces, user_id=7)
+    assert [item.id for item in after_re_pin_a] == [1, 2]
+
+
 @pytest.mark.asyncio
 async def test_set_pin_rejects_sixth_visible_pin_without_writing():
     repository = SimpleNamespace(
         lock_user=AsyncMock(),
-        list_for_user=AsyncMock(return_value=set(range(1, 6))),
+        list_for_user=AsyncMock(return_value=list(range(1, 6))),
         add_pin=AsyncMock(),
         remove_pin=AsyncMock(),
     )
@@ -87,7 +112,7 @@ async def test_set_pin_rejects_sixth_visible_pin_without_writing():
 async def test_set_pin_is_idempotent_for_existing_pin_even_at_limit():
     repository = SimpleNamespace(
         lock_user=AsyncMock(),
-        list_for_user=AsyncMock(return_value=set(range(1, 6))),
+        list_for_user=AsyncMock(return_value=list(range(1, 6))),
         add_pin=AsyncMock(),
         remove_pin=AsyncMock(),
     )
diff --git a/src/frontend/client/src/pages/knowledge/hooks/useSpaceActions.ts b/src/frontend/client/src/pages/knowledge/hooks/useSpaceActions.ts
index 361037536..e17c99d76 100644
--- a/src/frontend/client/src/pages/knowledge/hooks/useSpaceActions.ts
+++ b/src/frontend/client/src/pages/knowledge/hooks/useSpaceActions.ts
@@ -12,6 +12,7 @@ import { NotificationSeverity } from "~/common";
 import { useToastContext } from "~/Providers";
 import { useLocalize } from "~/hooks";
 import { extractKnowledgeActionErrorMessage } from "../errorUtils";
+import { applyPinOrderToSpaceList } from "../sidebar/spaceSort";
 
 interface UseSpaceActionsOptions {
     activeSpaceId?: string;
@@ -142,9 +143,10 @@ export function useSpaceActions({
             return;
         }
 
-        // Optimistic update
-        const updater = (list: KnowledgeSpace[]) => list.map(s => s.id === spaceId ? { ...s, isPinned: pinned } : s);
-        updateAllCaches(updater);
+        const previousGrouped = queryClient.getQueryData<GroupedKnowledgeSpaces>(["knowledgeSpaces", "grouped"]);
+
+        // Optimistic update: newly pinned spaces move to the front of the pinned block.
+        updateAllCaches((list) => applyPinOrderToSpaceList(list, spaceId, pinned));
 
         if (activeSpaceId === spaceId) {
             const space = targetList.find(s => s.id === spaceId);
@@ -156,9 +158,11 @@ export function useSpaceActions({
             queryClient.invalidateQueries({ queryKey: ["knowledgeSpaces"] });
             showToast({ message: pinned ? localize("com_knowledge.pinned") : localize("com_knowledge.unpinned"), severity: NotificationSeverity.SUCCESS });
         } catch {
-            // Rollback
-            const rollback = (list: KnowledgeSpace[]) => list.map(s => s.id === spaceId ? { ...s, isPinned: !pinned } : s);
-            updateAllCaches(rollback);
+            if (previousGrouped) {
+                queryClient.setQueryData(["knowledgeSpaces", "grouped"], previousGrouped);
+            } else {
+                updateAllCaches((list) => applyPinOrderToSpaceList(list, spaceId, !pinned));
+            }
             if (activeSpaceId === spaceId) {
                 const space = targetList.find(s => s.id === spaceId);
                 if (space) onSpaceSelect({ ...space, isPinned: !pinned });
diff --git a/src/frontend/client/src/pages/knowledge/portal/PortalKnowledgeWorkbench.tsx b/src/frontend/client/src/pages/knowledge/portal/PortalKnowledgeWorkbench.tsx
index 965f8af07..89ee2a590 100644
--- a/src/frontend/client/src/pages/knowledge/portal/PortalKnowledgeWorkbench.tsx
+++ b/src/frontend/client/src/pages/knowledge/portal/PortalKnowledgeWorkbench.tsx
@@ -463,12 +463,35 @@ export default function PortalKnowledgeWorkbench() {
             showToast({ message: "最多置顶 5 个知识库", severity: NotificationSeverity.INFO });
             return;
         }
+        const queryKey = ["knowledgeSpaces", "level", group.level];
+        const previousSpaces = queryClient.getQueryData<KnowledgeSpace[]>(queryKey);
+        if (previousSpaces) {
+            const target = previousSpaces.find((item) => item.id === space.id);
+            if (target) {
+                const updated = { ...target, isPinned: pinned };
+                const others = previousSpaces.filter((item) => item.id !== space.id);
+                queryClient.setQueryData<KnowledgeSpace[]>(
+                    queryKey,
+                    pinned
+                        ? [updated, ...others]
+                        : [
+                            ...others.filter((item) => item.isPinned),
+                            updated,
+                            ...others.filter((item) => !item.isPinned),
+                        ],
+                );
+            }
+        }
+        setActiveSpace((prev) => prev?.id === space.id ? { ...prev, isPinned: pinned } : prev);
         try {
             await pinSpaceApi(space.id, pinned);
-            setActiveSpace((prev) => prev?.id === space.id ? { ...prev, isPinned: pinned } : prev);
             await queryClient.invalidateQueries({ queryKey: ["knowledgeSpaces"] });
             showToast({ message: pinned ? "已置顶" : "已取消置顶", severity: NotificationSeverity.SUCCESS });
         } catch {
+            if (previousSpaces) {
+                queryClient.setQueryData(queryKey, previousSpaces);
+            }
+            setActiveSpace((prev) => prev?.id === space.id ? { ...prev, isPinned: !pinned } : prev);
             showToast({ message: "操作失败", severity: NotificationSeverity.ERROR });
         }
     }, [queryClient, showToast]);
diff --git a/src/frontend/client/src/pages/knowledge/sidebar/KnowledgeSpaceSidebar.tsx b/src/frontend/client/src/pages/knowledge/sidebar/KnowledgeSpaceSidebar.tsx
index b1988570f..cd8b8cc6f 100644
--- a/src/frontend/client/src/pages/knowledge/sidebar/KnowledgeSpaceSidebar.tsx
+++ b/src/frontend/client/src/pages/knowledge/sidebar/KnowledgeSpaceSidebar.tsx
@@ -17,6 +17,9 @@ import {
     hasKnowledgeSpacePermission,
     useKnowledgeSpaceActionPermissions,
 } from "../hooks/useKnowledgeSpacePermissions";
+import { sortKnowledgeSpacesForSection } from "./spaceSort";
+
+export { applyPinOrderToSpaceList, sortKnowledgeSpacesForSection } from "./spaceSort";
 
 interface KnowledgeSpaceSidebarProps {
     activeSpaceId?: string;
@@ -64,23 +67,6 @@ function getSortLabel(sort: SpaceSortType, localize: any) {
     return sort === SpaceSortType.NAME ? localize("com_knowledge.name") : localize("com_knowledge.recently_updated");
 }
 
-export function sortKnowledgeSpacesForSection(
-    spaces: KnowledgeSpace[],
-    sortBy: SpaceSortType,
-): KnowledgeSpace[] {
-    return [...spaces].sort((a, b) => {
-        if (a.isPinned !== b.isPinned) {
-            return a.isPinned ? -1 : 1;
-        }
-        if (sortBy === SpaceSortType.NAME) {
-            return a.name.localeCompare(b.name, undefined, { numeric: true, sensitivity: "base" });
-        }
-        const timeA = Date.parse(a.updatedAt || "") || 0;
-        const timeB = Date.parse(b.updatedAt || "") || 0;
-        return timeB - timeA;
-    });
-}
-
 export function getNextSectionSorts(
     currentSorts: Record<SpaceLevel, SpaceSortType>,
     level: SpaceLevel,
diff --git a/src/frontend/client/src/pages/knowledge/sidebar/spaceSort.test.ts b/src/frontend/client/src/pages/knowledge/sidebar/spaceSort.test.ts
new file mode 100644
index 000000000..df5c8428d
--- /dev/null
+++ b/src/frontend/client/src/pages/knowledge/sidebar/spaceSort.test.ts
@@ -0,0 +1,82 @@
+import { KnowledgeSpace, SpaceLevel, SpaceSortType } from "~/api/knowledge";
+import { applyPinOrderToSpaceList, sortKnowledgeSpacesForSection } from "./spaceSort";
+
+function space(
+    id: string,
+    overrides: Partial<KnowledgeSpace> = {},
+): KnowledgeSpace {
+    return {
+        id,
+        name: id,
+        description: "",
+        icon: "",
+        visibility: "private" as KnowledgeSpace["visibility"],
+        isReleased: true,
+        isPinned: false,
+        spaceLevel: SpaceLevel.PUBLIC,
+        updatedAt: "2026-01-01T00:00:00Z",
+        ...overrides,
+    };
+}
+
+describe("sortKnowledgeSpacesForSection", () => {
+    it("keeps relative order among pinned spaces", () => {
+        const input = [
+            space("b", { isPinned: true, name: "B", updatedAt: "2026-01-02T00:00:00Z" }),
+            space("a", { isPinned: true, name: "A", updatedAt: "2026-01-03T00:00:00Z" }),
+            space("c", { isPinned: false, name: "C" }),
+        ];
+
+        const byName = sortKnowledgeSpacesForSection(input, SpaceSortType.NAME);
+        expect(byName.map((item) => item.id)).toEqual(["b", "a", "c"]);
+
+        const byTime = sortKnowledgeSpacesForSection(input, SpaceSortType.UPDATE_TIME);
+        expect(byTime.map((item) => item.id)).toEqual(["b", "a", "c"]);
+    });
+
+    it("still floats pinned spaces above unpinned ones", () => {
+        const input = [
+            space("c", { isPinned: false, name: "C" }),
+            space("a", { isPinned: true, name: "A" }),
+            space("b", { isPinned: false, name: "B" }),
+        ];
+
+        expect(
+            sortKnowledgeSpacesForSection(input, SpaceSortType.NAME).map((item) => item.id),
+        ).toEqual(["a", "b", "c"]);
+    });
+});
+
+describe("applyPinOrderToSpaceList", () => {
+    it("moves a newly pinned space to the front", () => {
+        const input = [
+            space("a", { isPinned: true }),
+            space("b", { isPinned: false }),
+            space("c", { isPinned: false }),
+        ];
+
+        expect(applyPinOrderToSpaceList(input, "c", true).map((item) => item.id)).toEqual([
+            "c",
+            "a",
+            "b",
+        ]);
+        expect(applyPinOrderToSpaceList(input, "c", true)[0].isPinned).toBe(true);
+    });
+
+    it("places an unpinned space after the remaining pinned block", () => {
+        const input = [
+            space("b", { isPinned: true }),
+            space("a", { isPinned: true }),
+            space("c", { isPinned: false }),
+        ];
+
+        expect(applyPinOrderToSpaceList(input, "a", false).map((item) => item.id)).toEqual([
+            "b",
+            "a",
+            "c",
+        ]);
+        expect(applyPinOrderToSpaceList(input, "a", false).find((item) => item.id === "a")?.isPinned).toBe(
+            false,
+        );
+    });
+});
diff --git a/src/frontend/client/src/pages/knowledge/sidebar/spaceSort.ts b/src/frontend/client/src/pages/knowledge/sidebar/spaceSort.ts
new file mode 100644
index 000000000..59224c879
--- /dev/null
+++ b/src/frontend/client/src/pages/knowledge/sidebar/spaceSort.ts
@@ -0,0 +1,42 @@
+import { KnowledgeSpace, SpaceSortType } from "~/api/knowledge";
+
+export function sortKnowledgeSpacesForSection(
+    spaces: KnowledgeSpace[],
+    sortBy: SpaceSortType,
+): KnowledgeSpace[] {
+    return [...spaces].sort((a, b) => {
+        if (a.isPinned !== b.isPinned) {
+            return a.isPinned ? -1 : 1;
+        }
+        // Preserve API / optimistic pin-recency order within the pinned block.
+        if (a.isPinned && b.isPinned) {
+            return 0;
+        }
+        if (sortBy === SpaceSortType.NAME) {
+            return a.name.localeCompare(b.name, undefined, { numeric: true, sensitivity: "base" });
+        }
+        const timeA = Date.parse(a.updatedAt || "") || 0;
+        const timeB = Date.parse(b.updatedAt || "") || 0;
+        return timeB - timeA;
+    });
+}
+
+/** Move a space to the front of its list when pinning; keep relative order otherwise. */
+export function applyPinOrderToSpaceList(
+    list: KnowledgeSpace[],
+    spaceId: string,
+    pinned: boolean,
+): KnowledgeSpace[] {
+    const target = list.find((space) => space.id === spaceId);
+    if (!target) {
+        return list;
+    }
+    const updated = { ...target, isPinned: pinned };
+    const others = list.filter((space) => space.id !== spaceId);
+    if (pinned) {
+        return [updated, ...others];
+    }
+    const pinnedItems = others.filter((space) => space.isPinned);
+    const unpinnedItems = others.filter((space) => !space.isPinned);
+    return [...pinnedItems, updated, ...unpinnedItems];
+}