Add iPhone target with shared data layer and persistent cache

Two-target restructure: shared sources (models, services, settings,
extensions, team logos) move into Shared/, consumed by both the
existing macOS menu bar app and a new iOS app. MainService no longer
imports AppKit — platform code attaches via a MainServiceObserver
protocol (MacObserverAdapter wires back to MenuManager / StatusItemManager
/ NotificationManager).

iPhone app is a single SwiftUI page mirroring the macOS menu (playoff
round + yesterday/today/tomorrow), with a gear-icon settings sheet
(display option + IndieAbout for license/changelog). Persistent JSON
snapshot in Application Support paints last-known data on cold launch;
"Updated …" header escalates secondary → orange (>5min) → red (>30min)
so staleness is visually unmistakable. Foreground polling, scenePhase
refresh, and pull-to-refresh; no notifications on iOS in v1.

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## April 2026
 
+- New iPhone target (`IceGlass-iOS`): single-page SwiftUI app mirroring the macOS menu's playoff round + yesterday/today/tomorrow content, with a gear-icon settings sheet (display option + IndieAbout)
+- Persistent JSON cache (`Shared/Services/NHLDataCache.swift`) stored in Application Support so iPhone cold launches paint last-known data immediately; surfaced with a stale-aware "Updated …" header (secondary → orange after 5 min → red after 30 min)
+- Shared code refactored into a top-level `Shared/` directory consumed by both targets; introduced `MainServiceObserver` protocol so `MainService` no longer imports AppKit
 - Team logo download pipeline now produces 128×128 transparent squares directly (via a new `Scripts/square_logo.swift` helper called from `download_team_logos.sh`), so notification attachments can ship the bundled PNG as-is and the banner thumbnail renders crisply without runtime compositing
 - Game state tag (PRE / LIVE / CRIT / OVER / FINAL / OFF) now surfaced on each daily game row and on live series rows in the ROUND block
 - Playoff series rows in the ROUND block are always clickable (open the NHL series page) and mark completed series as "Final"