fix: inline comment continuity, unified-mode comment positioning, and macOS media prompt

[huhamhire]

A batch of PR-review bug fixes.

1. Keep inline editors alive across a comments/drafts refresh (fix(diff))

A prior fix gave the inline comment zones a reconcile-in-place controller, but two gaps still interrupted an open inline editor on every poll:

• useDiffComments called setComments() unconditionally, so an unchanged poll still produced a fresh comments array. That churned the mentionCandidates memo, whose identity change re-ran useDraftZones. Now it bails on structural equality (reusing sameCommentList, extracted to a shared commentEquality module) so an unchanged poll keeps the old reference — mirroring what the activity view already does.
• useDraftZones used the one-shot mount, so a real drafts/comments change tore down and rebuilt every DraftZone root, dropping an open draft editor's edit mode / focus / caret. It now uses the same split structural/content effect + persistent createInlineZones controller as useCommentZones, reconciling draft zones by (side, line) key. A surviving draft re-renders in place; only a removed draft (deleted / published / file switch) unmounts.

The activity timeline already bailed via sameCommentList and needs no change.

2. Anchor inline comments to the actual render mode after auto-degrade (fix(diff))

renderSideBySide threaded through the diff view is the toolbar intent, not the mode Monaco actually renders. When the pane is too narrow Monaco auto-degrades side-by-side → inline while the intent stays true, so old-side (base) items got routed to the original editor Monaco has hidden — a published old-side inline comment then had no visible position, and its glyph dot / overview tick vanished too.

• Introduces a single source of truth for the actual mode (useActualRenderSideBySide, reading Monaco's .monaco-diff-editor.side-by-side class reactively) and feeds it to useCommentZones / useDraftZones / useLineCommentAdder / useSelectionCapture.
• useCommentZones remaps old-side glyph/overview decorations onto the modified editor when actually inline (also fixes old-side markers in explicitly-chosen unified — a latent bug).
• Fixes old-side anchor reveal: the nav anchor dropped side (App/PrPanel/PublishReviewModal/notification) and useDiffNav hardcoded side:'new' with no remap. side is now threaded through the anchor (incl. the notification:activate IPC event) and, at reveal time, the live actual mode decides the target: an old-side reveal uses the original editor only when visible, otherwise remaps the old line onto the modified editor. The cross-file search jump reuses the same path.

3. Stop the unexpected Apple Music / media-library permission prompt on macOS (fix(mac))

On macOS the app popped a "would like to access Apple Music, your music and video activity, and your media library" prompt on launch. Not from packaging (no music entitlement, no NSAppleMusicUsageDescription): it's Chromium's macOS "Now Playing" / media-session integration querying the MediaPlayer framework. The app plays no media, so the permission is unexpected. Disables the MediaSessionService and HardwareMediaKeyHandling features at mac startup (before app.whenReady()).

⚠️ This one is macOS-only and was developed on Windows — needs verification on a macOS build to confirm the prompt no longer appears.

Checks

lint + typecheck (all projects) + build (desktop) pass locally.