feat: massive chat reliability + UX pass (web/desktop/mobile/vscode) (#593)

## Added Features
- Add VS Code save-as-image flow for assistant messages via webview bridge + native save dialog.
- Add hourly desktop update checks after startup.
- Add new tool output display mode: `Changes` (auto-expand edit/write/patch only; keep activity expanded; mode guidance text).
- Add GitHub PR attachment flow in chat input with PR picker + attached PR chip/details.
- Add mobile overlay presentation for GitHub Issue and PR pickers (shared with desktop picker content).

## Fixes
- Save-gate project icon updates until explicit Save; allow icon removal with same save-gated behavior.
- Restore clickable chat action buttons in sticky header mode (desktop + Firefox hit-target issue).
- Clamp sticky user messages to bounded chat height and allow internal scrolling.
- Prevent drawer context crash during iPad/tablet orientation switching.
- Improve text-selection action menu placement on narrow screens.
- Move assistant message time into clock tooltip; keep duration display clean.
- Hide `Link GitHub Issue` row in VS Code chat input area (GitHub flow is not yet ready there).
- Remove laggy close animation in text-selection popover; keep open motion/positioning behavior.
- Fetch branches when picker opens and cache empty; show loading state instead of false “No branches found”.
- Fix share-image export metadata rendering (theme background resolution, timestamp rendering, footer alignment).
- Scope MCP services status/toggles to active directory to avoid cross-project leakage.
- Improve long user-message clamp behavior (40% cap variant, hidden scrollbar, scroll shadows, expansion detection).
- Fix desktop `Check for Updates` menu handler; prevent duplicate checks; show clear success/error toasts.
- Stabilize long user-message scrolling behavior (follow-up hardening).
- Avoid premature web update failure on slower servers.
- Restore user message image previews + fullscreen gallery navigation payload.
- Repair desktop chat drag-and-drop image attachments when native drop coords are missing.
- Move GitHub issue linking entry into Add attachment menu.
- Align header context usage percentage visuals with context panel.
- Align `@` file search with active project in all runtimes.
- Route `@` file discovery through OpenCode SDK `find.files`; remove legacy `/api/fs/search` reliance.
- Make chat `@` mention behavior consistent with files-style behavior.
- Keep status-row todos in stable order after status changes; add compact status icons; replace noisy priority labels.

## Refactors / UX Consistency
- Simplify chat attachment model and remove project file picker path.
- Keep composer focused on `@` mention file flow.
- Use direct `Attach files` action in VS Code instead of attachment dropdown path.
- Unify issue/PR picker behavior between desktop and mobile overlays.

packages/web/server/index.js

@@ -63,8 +63,6 @@ const OPENCHAMBER_VERSION = (() => {
   return 'unknown';
 })();
 const fsPromises = fs.promises;
-const DEFAULT_FILE_SEARCH_LIMIT = 60;
-const MAX_FILE_SEARCH_LIMIT = 400;
 const FILE_SEARCH_MAX_CONCURRENCY = 5;
 const FILE_SEARCH_EXCLUDED_DIRS = new Set([
   'node_modules',
@@ -1997,7 +1995,7 @@ const sanitizeSettingsUpdate = (payload) => {
   }
   if (typeof candidate.toolCallExpansion === 'string') {
     const mode = candidate.toolCallExpansion.trim();
-    if (mode === 'collapsed' || mode === 'activity' || mode === 'detailed') {
+    if (mode === 'collapsed' || mode === 'activity' || mode === 'detailed' || mode === 'changes') {
       result.toolCallExpansion = mode;
     }
   }
@@ -12364,53 +12362,6 @@ async function main(options = {}) {
     }
   });
 
-  app.get('/api/fs/search', async (req, res) => {
-    const rawRoot = typeof req.query.root === 'string' && req.query.root.trim().length > 0
-      ? req.query.root.trim()
-      : typeof req.query.directory === 'string' && req.query.directory.trim().length > 0
-        ? req.query.directory.trim()
-        : os.homedir();
-  const rawQuery = typeof req.query.q === 'string' ? req.query.q : '';
-  const includeHidden = req.query.includeHidden === 'true';
-  const respectGitignore = req.query.respectGitignore !== 'false';
-  const limitParam = typeof req.query.limit === 'string' ? Number.parseInt(req.query.limit, 10) : undefined;
-    const parsedLimit = Number.isFinite(limitParam) ? Number(limitParam) : DEFAULT_FILE_SEARCH_LIMIT;
-    const limit = Math.max(1, Math.min(parsedLimit, MAX_FILE_SEARCH_LIMIT));
-
-    try {
-      const resolvedRoot = path.resolve(normalizeDirectoryPath(rawRoot));
-      const stats = await fsPromises.stat(resolvedRoot);
-      if (!stats.isDirectory()) {
-        return res.status(400).json({ error: 'Specified root is not a directory' });
-      }
-
-      const files = await searchFilesystemFiles(resolvedRoot, {
-        limit,
-        query: rawQuery || '',
-        includeHidden,
-        respectGitignore,
-      });
-      res.json({
-        root: resolvedRoot,
-        count: files.length,
-        files
-      });
-    } catch (error) {
-      console.error('Failed to search filesystem:', error);
-      const err = error;
-      if (err && typeof err === 'object' && 'code' in err) {
-        const code = err.code;
-        if (code === 'ENOENT') {
-          return res.status(404).json({ error: 'Directory not found' });
-        }
-        if (code === 'EACCES') {
-          return res.status(403).json({ error: 'Access to directory denied' });
-        }
-      }
-      res.status(500).json({ error: (error && error.message) || 'Failed to search files' });
-    }
-  });
-
   let ptyProviderPromise = null;
   const getPtyProvider = async () => {
     if (ptyProviderPromise) {