fix(kilo-ui): fix user message copy button unclickable in sidebar (#7501)

* fix(kilo-ui): fix user message copy button unclickable in sidebar

The copy wrapper height (10px) was smaller than the button (20px),
causing the button to overflow outside the parent's bounding box.
Hovering the overflowed region lost the parent :hover state, which
reverted pointer-events to none and opacity to 0 before the click
could register.

Set wrapper height to 20px to fully contain the button and remove
the overflow:hidden/visible toggle that is no longer needed.

Fixes regression from #7098.

* chore: update visual regression baselines

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

packages/kilo-ui/src/components/message-part.css

@@ -150,15 +150,15 @@ html[data-theme="kilo-vscode"] [data-component="bash-output"] {
   margin-bottom: 0px;
 }
 
-/* User message copy button: tiny reserved space, button overflows on hover.
- * height:2px keeps layout stable; overflow:hidden clips the invisible button;
- * on hover overflow:visible lets the button appear without shifting content. */
+/* User message copy button: collapse wrapper when idle, show on hover.
+ * The wrapper must be tall enough to fully contain the button (20px)
+ * so that hovering the button keeps [data-component="user-message"]
+ * hovered — otherwise :hover is lost and pointer-events/opacity revert. */
 [data-component="user-message"] {
   [data-slot="user-message-copy-wrapper"] {
     min-height: 0;
-    height: 10px;
+    height: 20px;
     margin-top: 0;
-    overflow: hidden;
 
     [data-slot="user-message-meta-wrap"] {
       display: none;
@@ -169,11 +169,6 @@ html[data-theme="kilo-vscode"] [data-component="bash-output"] {
       height: 20px;
     }
   }
-
-  &:hover [data-slot="user-message-copy-wrapper"],
-  &:focus-within [data-slot="user-message-copy-wrapper"] {
-    overflow: visible;
-  }
 }
 
 [data-component="question-answers"] {

packages/kilo-ui/tests/visual-regression.spec.ts-snapshots/components-messagepart/full-conversation-turn-chromium-linux.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:9cad4954b9ac5c0d1a245d14b3ab51836217479870c39589a55eb862c4247aa9
-size 18902
+oid sha256:81fd232992e804e8e0b3453c4e77d358f8c24dd7495b354b8d7de24c7a43724c
+size 18986

packages/kilo-ui/tests/visual-regression.spec.ts-snapshots/components-messagepart/user-message-story-chromium-linux.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:876fba84b341bffa55bedb3c6d3384c5099c9a1d9336a3090b429b87e1256110
-size 4149
+oid sha256:4b690e1cba9e1a7a4eef86162c762092f5908f2d498f0d77f48c44fef1fd44ff
+size 4242

packages/kilo-ui/tests/visual-regression.spec.ts-snapshots/components-sessionturn/default-chromium-linux.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:0fc349b25120ba40eaf3f6e6cb9adf268a0433c6a4b4e723f5a9957c555aec25
-size 29267
+oid sha256:71a4c5ce0d2bd00ac8428a65e3c4db6c0455720cac5467f8f483a9708cea8765
+size 29370

packages/kilo-ui/tests/visual-regression.spec.ts-snapshots/components-sessionturn/with-steps-expanded-chromium-linux.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:c67bd29525bc38133cc5271d0467e85e131a0bd41313a4033836e7a6bc5e02e2
-size 26312
+oid sha256:71a4c5ce0d2bd00ac8428a65e3c4db6c0455720cac5467f8f483a9708cea8765
+size 29370

packages/kilo-ui/tests/visual-regression.spec.ts-snapshots/components-sessionturn/working-chromium-linux.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:640fabcec21e9e8e2251e1b347966790d347af9c0b438ca4dc9bc118819069f2
-size 4562
+oid sha256:4272e7e538d95ee3c7010dca5711a53643573c0efed2c527d6db58ef23d6c086
+size 4627