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/ui/src/components/layout/SidebarFilesTree.tsx

@@ -446,50 +446,6 @@ export const SidebarFilesTree: React.FC = () => {
 
   // --- Fuzzy search scoring (matching FilesView) ---
 
-  const fuzzyScore = React.useCallback((query: string, candidate: string): number | null => {
-    const q = query.trim().toLowerCase();
-    if (!q) return 0;
-
-    const c = candidate.toLowerCase();
-    let score = 0;
-    let lastIndex = -1;
-    let consecutive = 0;
-
-    for (let i = 0; i < q.length; i += 1) {
-      const ch = q[i];
-      if (!ch || ch === ' ') continue;
-
-      const idx = c.indexOf(ch, lastIndex + 1);
-      if (idx === -1) return null;
-
-      const gap = idx - lastIndex - 1;
-      if (gap === 0) {
-        consecutive += 1;
-      } else {
-        consecutive = 0;
-      }
-
-      score += 10;
-      score += Math.max(0, 18 - idx);
-      score -= Math.max(0, gap);
-
-      if (idx === 0) {
-        score += 12;
-      } else {
-        const prev = c[idx - 1];
-        if (prev === '/' || prev === '_' || prev === '-' || prev === '.' || prev === ' ') {
-          score += 10;
-        }
-      }
-
-      score += consecutive > 0 ? 12 : 0;
-      lastIndex = idx;
-    }
-
-    score += Math.max(0, 24 - Math.round(c.length / 3));
-    return score;
-  }, []);
-
   React.useEffect(() => {
     if (!currentDirectory) {
       setSearchResults([]);
@@ -504,34 +460,20 @@ export const SidebarFilesTree: React.FC = () => {
       return;
     }
 
-    const normalizedQueryLower = trimmedQuery.toLowerCase();
     let cancelled = false;
     setSearching(true);
 
     searchFiles(currentDirectory, trimmedQuery, 150, {
       includeHidden: showHidden,
       respectGitignore: !showGitignored,
+      type: 'file',
     })
       .then((hits) => {
         if (cancelled) return;
 
         const filtered = hits.filter((hit) => showGitignored || !shouldIgnorePath(hit.path));
 
-        const ranked = filtered
-          .map((hit) => {
-            const label = hit.relativePath || hit.name || hit.path;
-            const score = fuzzyScore(normalizedQueryLower, label);
-            return score === null ? null : { hit, score, labelLength: label.length };
-          })
-          .filter(Boolean) as Array<{ hit: typeof hits[0]; score: number; labelLength: number }>;
-
-        ranked.sort((a, b) => (
-          b.score - a.score
-          || a.labelLength - b.labelLength
-          || a.hit.path.localeCompare(b.hit.path)
-        ));
-
-        const mapped: FileNode[] = ranked.map(({ hit }) => ({
+        const mapped: FileNode[] = filtered.map((hit) => ({
           name: hit.name,
           path: normalizePath(hit.path),
           type: 'file',
@@ -555,7 +497,7 @@ export const SidebarFilesTree: React.FC = () => {
     return () => {
       cancelled = true;
     };
-  }, [currentDirectory, debouncedSearchQuery, fuzzyScore, searchFiles, showHidden, showGitignored]);
+  }, [currentDirectory, debouncedSearchQuery, searchFiles, showHidden, showGitignored]);
 
   // --- Git status helpers (matching FilesView) ---