fix(app): settings live-apply — font on open terminals, daemon uptime

- Font change now applies to already-open terminals: the WebGL renderer
  caches glyphs in a texture atlas keyed by the old font/size, so the live
  re-apply effect now calls webglAddon.clearTextureAtlas() (via a new ref)
  after updating fontFamily/fontSize, before refitting.
- Daemon uptime now reflects a restart: the Settings daemon section ticks
  every second for live uptime, and Stop/Restart trigger an onReload callback
  that re-fetches health/status in App so a restarted daemon's new
  started_at_ms is shown instead of the stale value.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/src/TerminalView.tsx

@@ -22,6 +22,7 @@ export function TerminalView({ surfaceId, font, palette }: { surfaceId: string;
   const ref = useRef<HTMLDivElement>(null);
   const termRef = useRef<Terminal | null>(null);
   const fitRef = useRef<FitAddon | null>(null);
+  const webglRef = useRef<WebglAddon | null>(null);
 
   useEffect(() => {
     if (!ref.current) return;
@@ -39,7 +40,9 @@ export function TerminalView({ surfaceId, font, palette }: { surfaceId: string;
     termRef.current = term;
 
     try {
-      term.loadAddon(new WebglAddon());
+      const webgl = new WebglAddon();
+      term.loadAddon(webgl);
+      webglRef.current = webgl;
     } catch {
       // webgl unavailable → fall back to canvas/dom renderer silently
     }
@@ -99,6 +102,7 @@ export function TerminalView({ surfaceId, font, palette }: { surfaceId: string;
       term.dispose();
       termRef.current = null;
       fitRef.current = null;
+      webglRef.current = null;
     };
   }, [surfaceId]); // eslint-disable-line react-hooks/exhaustive-deps
 
@@ -110,6 +114,10 @@ export function TerminalView({ surfaceId, font, palette }: { surfaceId: string;
     if (font) {
       t.options.fontFamily = `'${font.family}', monospace`;
       t.options.fontSize = font.size;
+      // The WebGL renderer caches rasterized glyphs in a texture atlas keyed by
+      // the old font/size; without clearing it the grid keeps rendering stale
+      // glyphs after a font change.
+      webglRef.current?.clearTextureAtlas();
     }
     if (palette) t.options.theme = xtermTheme(palette);
     requestAnimationFrame(() => { try { fitRef.current?.fit(); } catch { /* ignore */ } });