feat: add /reload action to reboot the instance from disk

Reboots the per-directory instance, reloading config, skills, agents,
commands, and MCP prompts changed on disk without restarting the
server. Sessions and history are preserved; only the per-directory
instance caches are torn down and rebuilt.

Server: POST /instance/reload wraps the existing atomic
InstanceStore.reload path (the same one project.git.init uses). The
rebuild completes before the 200 response, so clients can refetch with
no race. Returns 409 ConflictError while a session is actively
running. Emits the existing server.instance.disposed SSE event, which
the TUI and extension already use to auto-refetch.

CLI: /reload palette command calls the endpoint; the TUI already
bootstraps on server.instance.disposed.

Extension: /reload slash command, a reload button in the task header
and settings panel, and a Kilo Code: Reload Config and Skills command
palette entry. The handler clears the command cache and reuses
reloadAfterAuthChange to re-fetch config, providers, agents, skills,
and commands. Reload targets the current session's directory so Agent
Manager worktree sessions reload their own worktree instance rather
than the workspace root.

SDK: regenerate so client.instance.reload is available to external
integrations.

packages/opencode/test/kilocode/instance-reload.test.ts

@@ -0,0 +1,43 @@
+import { describe, expect, it } from "bun:test"
+import { hasBusySession } from "@/kilocode/server/httpapi/handlers/instance-reload"
+import type { SessionStatus } from "@/session/status"
+import { SessionID } from "@/session/schema"
+
+const entries = (items: [string, SessionStatus.Info][]) =>
+  items.map(([k, v]) => [k as SessionID, v] as [SessionID, SessionStatus.Info])
+
+describe("instance-reload hasBusySession", () => {
+  it("returns false for an empty map", () => {
+    expect(hasBusySession(new Map(entries([])))).toBe(false)
+  })
+
+  it("returns false when all sessions are idle", () => {
+    expect(
+      hasBusySession(
+        new Map(
+          entries([
+            ["s1", { type: "idle" }],
+            ["s2", { type: "idle" }],
+          ]),
+        ),
+      ),
+    ).toBe(false)
+  })
+
+  it("returns true when any session is busy", () => {
+    expect(
+      hasBusySession(
+        new Map(
+          entries([
+            ["s1", { type: "idle" }],
+            ["s2", { type: "busy" }],
+          ]),
+        ),
+      ),
+    ).toBe(true)
+  })
+
+  it("returns true when the only session is busy", () => {
+    expect(hasBusySession(new Map(entries([["s1", { type: "busy" }]])))).toBe(true)
+  })
+})