feat(clients): tiered stats overlay everywhere — Compact/Normal/Detailed on every platform

Ship the Android client's 3-tier stats-overlay semantics in every other client
(design/stats-unification.md vocabulary): Off → Compact (one line: fps · e2e ms ·
Mb/s + loss flag) → Normal (mode + e2e p50/p95 + loss counters) → Detailed
(decoder path, HDR tag, per-stage latency equation).

Apple: new StatsVerbosity in PunktfunkKit persisted under punktfunk.statsVerbosity
(migrates the legacy hudEnabled bool: explicit off → Off, else Normal). The
existing three-finger tap (TouchMouse, trackpad/pointer modes only — touch
passthrough untouched) now cycles the tiers instead of toggling, matching
Android; ⌃⌥⇧S (menu + captured-state monitor) cycles the same ladder. Tiered
StreamHUDView (compact glass pill / headline HUD / full equation HUD); the iOS
corner disconnect also shows in Compact (the pill carries no button). Tier
pickers on iOS, macOS, tvOS and the gamepad settings UI.

Session stack (Linux + Windows + Deck share punktfunk-session): shared
pf_client_core::trust::StatsVerbosity; Settings grows stats_verbosity with a
show_stats fallback, and writes keep the legacy bool in sync so pre-tier
binaries reading the same JSON agree on off vs on. Ctrl+Alt+Shift+S cycles the
tier and re-renders the OSD immediately from the last stats window; the stdout
stats: line always carries the full Detailed text so the shell status card and
scripts keep a stable shape; --stats bumps Off → Normal without demoting a
richer tier. Tier pickers in the GTK dialog, the WinUI settings page and the
console-UI settings row; shortcut copy updated (GTK shortcuts window, Windows
help, session README). The Windows legacy builtin path keeps its bool HUD.

Tests: tier migration/round-trip in trust.rs, tiered stats_text output in
pf-presenter.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

clients/apple/Sources/PunktfunkKit/Support/DefaultsKeys.swift

@@ -67,9 +67,15 @@ public enum DefaultsKey {
     public static let libraryEnabled = "punktfunk.libraryEnabled"
     /// macOS: take the window fullscreen while streaming and restore it on the host list. On by default.
     public static let fullscreenWhileStreaming = "punktfunk.fullscreenWhileStreaming"
-    /// Show the streaming statistics overlay (mode/fps/throughput/latency). On by default; toggle
-    /// while streaming with ⌃⌥⇧S (the cross-client Ctrl+Alt+Shift+S; macOS / hardware keyboard).
+    /// LEGACY (pre-tiered overlay): the old boolean stats-overlay toggle. Kept ONLY as the
+    /// migration fallback `StatsVerbosity.current` reads when `statsVerbosity` was never
+    /// written (absent-or-true → .normal, explicit false → .off). Never written anymore.
     public static let hudEnabled = "punktfunk.hudEnabled"
+    /// The statistics overlay tier — a `StatsVerbosity` raw value ("off"/"compact"/"normal"/
+    /// "detailed"). Absent → migrated from the legacy `hudEnabled` bool (see above). Cycle it
+    /// while streaming with ⌃⌥⇧S (the cross-client Ctrl+Alt+Shift+S; macOS / hardware
+    /// keyboard) or a three-finger tap (touch), matching the Android client.
+    public static let statsVerbosity = "punktfunk.statsVerbosity"
     /// Which corner the statistics overlay sits in — a `HUDPlacement` raw value
     /// ("topLeading"/"topTrailing"/"bottomLeading"/"bottomTrailing"). Default top-trailing.
     public static let hudPlacement = "punktfunk.hudPlacement"