feat: improve VS Code dev flow and stabilize sidebar/chat behavior (#754)

* fix: improve session sidebar tooltip and truncation behavior

- Keep new-draft tooltip anchored to its trigger button
- Fix minimal-mode worktree/group header text truncation
- Tune minimal-mode right padding to reduce early label clipping

* fix: render reasoning through markdown pipeline

- Use Streamdown rendering for reasoning in live chat mode
- Remove italic styling from reasoning text
- Render expanded reasoning content with MarkdownRenderer

* chore: remove legacy electron dependencies

- Removed unused Electron packages from root and UI manifests
- Deleted obsolete Electron context menu type declaration
- Regenerated lockfile after dependency cleanup

* fix: handle non-repository folders in git status API

- Prevent 500 errors when status is requested outside a valid Git repo
- Improve repository detection using `git rev-parse --git-dir`
- Reduce noisy server logs for expected non-repo status checks

* fix unloaded session chat layout flicker

* fix: reduce noisy TTS status polling

Cache and dedupe TTS status requests, and only check provider availability when the related voice features are enabled so disabled voice setups stay quiet.

* perf: throttle background PR git status refreshes

* fix: improve VS Code Explorer file drop mentions in chat

- Add Explorer context action to insert selected files as @mentions.
- Handle Explorer drag-and-drop to prefill @file mentions instead of attachments.
- Prevent duplicate plain-path text when dropping multiple files.

* fix: deduplicate recent sessions in VS Code sidebar

- Hide sessions from main list when already shown in recent
- Apply dedup only in VS Code runtime
- Keep session search behavior unchanged

* feat: add true HMR dev flow for VS Code extension

- Load VS Code webview from Vite dev server with React refresh preamble
- Add `vscode:dev` runner that starts watchers and opens Extension Development Host
- Update VS Code dev docs and scripts to use the new HMR startup flow

* feat: polish VS Code session sidebar and attachment UX

- Add resizable sessions sidebar in VS Code layout
- Tighten session list spacing and hover behavior in VS Code
- Remove bulk file/image attach success toasts while keeping error toasts

packages/vscode/src/extension.ts

@@ -269,6 +269,66 @@ export async function activate(context: vscode.ExtensionContext) {
     })
   );
 
+  context.subscriptions.push(
+    vscode.commands.registerCommand('openchamber.attachExplorerToChat', async (resource?: vscode.Uri, resources?: vscode.Uri[]) => {
+      const uriCandidates: vscode.Uri[] = [];
+      if (Array.isArray(resources)) {
+        uriCandidates.push(...resources.filter((entry): entry is vscode.Uri => entry instanceof vscode.Uri));
+      }
+      if (resource instanceof vscode.Uri) {
+        uriCandidates.push(resource);
+      }
+      if (uriCandidates.length === 0) {
+        const activeEditorUri = vscode.window.activeTextEditor?.document.uri;
+        if (activeEditorUri) {
+          uriCandidates.push(activeEditorUri);
+        }
+      }
+
+      const uniqueUris = Array.from(new Map(uriCandidates.map((uri) => [uri.toString(), uri])).values());
+      const mentionPaths: string[] = [];
+      const skippedEntries: string[] = [];
+
+      for (const uri of uniqueUris) {
+        if (uri.scheme !== 'file') {
+          skippedEntries.push(uri.toString());
+          continue;
+        }
+
+        try {
+          const stat = await vscode.workspace.fs.stat(uri);
+          if ((stat.type & vscode.FileType.Directory) !== 0) {
+            skippedEntries.push(vscode.workspace.asRelativePath(uri, false));
+            continue;
+          }
+        } catch {
+          skippedEntries.push(vscode.workspace.asRelativePath(uri, false));
+          continue;
+        }
+
+        const relativePath = vscode.workspace.asRelativePath(uri, false).replace(/\\/g, '/').trim();
+        if (!relativePath) {
+          skippedEntries.push(uri.fsPath || uri.toString());
+          continue;
+        }
+        mentionPaths.push(relativePath);
+      }
+
+      if (mentionPaths.length === 0) {
+        vscode.window.showWarningMessage('OpenChamber: No file selected to mention');
+        return;
+      }
+
+      await vscode.commands.executeCommand('openchamber.openSidebar');
+      await new Promise((resolve) => setTimeout(resolve, 80));
+      chatViewProvider?.addFileMentions(mentionPaths);
+
+      if (skippedEntries.length > 0) {
+        vscode.window.showInformationMessage('OpenChamber: Some selected entries were skipped (folders or unsupported resources)');
+      }
+    })
+  );
+
   context.subscriptions.push(
     vscode.commands.registerCommand('openchamber.explain', async () => {
       const editor = vscode.window.activeTextEditor;