feat(desktop): Tier A desktop features — web side (P5-46/36/44/43/49/47/55/57)

Web half of the desktop feature wave. A shared bridge (`hooks/useTauri.ts`:
invokeTauri/isTauri/useTauriEvent) backs per-feature hooks that no-op in the
browser and drive the native Tauri commands (compiled in cinny-desktop):

- P5-46 useTauriCallPower — hold system awake while a call is active.
- P5-36 useTauriJumpList — Windows jump list of recent rooms → matrix: deep links.
- P5-44 useTauriThumbbar — taskbar Mute/Deafen/End; events toggle mic/sound/hangup.
- P5-43 useTauriSmtc — SMTC call state + button events.
- P5-49 useTauriNetwork — react to native network-change → mx.retryImmediately().
- P5-47 window chrome — opt-in `customWindowChromeAtom` + TDS `TitleBar`; DesktopChrome
  wrapper in App.tsx (zero layout impact when off) + a desktop-only settings toggle.
- P5-55 composer toolbar drag-reorder (settings order[] + pragmatic-drag-and-drop).
- P5-57 DraftIndicator — subtle "draft saved" cue in the composer.

Client-scoped hooks mount via TauriDesktopFeatures in ClientNonUIFeatures; window
chrome mounts at App level. Gates: tsc/eslint/prettier clean, build OK, 556 tests.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/features/room/DraftIndicator.tsx

@@ -0,0 +1,64 @@
+import React, { useEffect, useRef, useState } from 'react';
+import { useAtomValue } from 'jotai';
+import { Box, Text, config } from 'folds';
+
+import { roomIdToMsgDraftAtomFamily } from '../../state/room/roomInputDrafts';
+import { toPlainText } from '../../components/editor';
+import { DraftDot, DraftDotPulse, DraftIndicatorBase } from './DraftIndicator.css';
+
+const PULSE_DURATION = 600;
+
+type DraftIndicatorProps = {
+  roomId: string;
+};
+
+/**
+ * Subtle, non-distracting status shown near the composer when the current room
+ * has a persisted (unsent) message draft. It reacts to the shared draft atom
+ * (`roomIdToMsgDraftAtomFamily`) — the same source that backs the
+ * `draft-msg-${roomId}` localStorage persistence — so it never introduces a
+ * parallel persistence path.
+ *
+ * A short "Saved" pulse plays the moment a draft becomes persisted, then the
+ * indicator settles into a quiet, muted resting state. The pulse is gated behind
+ * `prefers-reduced-motion` in CSS, so motion-averse users only ever see the
+ * static label.
+ */
+export function DraftIndicator({ roomId }: DraftIndicatorProps) {
+  const draft = useAtomValue(roomIdToMsgDraftAtomFamily(roomId));
+  // Real content, not just an empty paragraph.
+  const hasDraft = toPlainText(draft, false).trim().length > 0;
+
+  const [pulse, setPulse] = useState(false);
+  const hadDraft = useRef(false);
+
+  useEffect(() => {
+    if (hasDraft && !hadDraft.current) {
+      hadDraft.current = true;
+      setPulse(true);
+      const timeout = setTimeout(() => setPulse(false), PULSE_DURATION);
+      return () => clearTimeout(timeout);
+    }
+    hadDraft.current = hasDraft;
+    return undefined;
+  }, [hasDraft]);
+
+  if (!hasDraft) return null;
+
+  return (
+    <Box
+      className={DraftIndicatorBase}
+      as="span"
+      shrink="No"
+      alignItems="Center"
+      gap="200"
+      style={{ padding: `0 ${config.space.S100}` }}
+      aria-hidden
+    >
+      <span className={`${DraftDot}${pulse ? ` ${DraftDotPulse}` : ''}`} />
+      <Text as="span" size="T200" priority="300">
+        Draft saved
+      </Text>
+    </Box>
+  );
+}