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/webviewDevServer.ts

@@ -0,0 +1,36 @@
+import * as vscode from 'vscode';
+
+const DEFAULT_WEBVIEW_DEV_SERVER_URL = 'http://localhost:5173';
+
+const normalizeUrl = (value: string): string | null => {
+  const trimmed = value.trim();
+  if (!trimmed) {
+    return null;
+  }
+  try {
+    const parsed = new URL(trimmed);
+    if (parsed.protocol !== 'http:' && parsed.protocol !== 'https:') {
+      return null;
+    }
+    return parsed.toString().replace(/\/$/, '');
+  } catch {
+    return null;
+  }
+};
+
+export const resolveWebviewDevServerUrl = (context: vscode.ExtensionContext): string | null => {
+  if (context.extensionMode !== vscode.ExtensionMode.Development) {
+    return null;
+  }
+
+  if (process.env.OPENCHAMBER_DISABLE_WEBVIEW_HMR === '1') {
+    return null;
+  }
+
+  const configured = normalizeUrl(process.env.OPENCHAMBER_VSCODE_WEBVIEW_URL ?? '');
+  if (configured) {
+    return configured;
+  }
+
+  return DEFAULT_WEBVIEW_DEV_SERVER_URL;
+};