Add game center, per-model shuffle, audio focus fixes, README, tests

- README.md with build/architecture overview
- Game Center screen with at-bat timeline, pitch sequence, spray chart,
  and strike zone component views
- VideoShuffle service: per-model bucketed random selection with
  no-back-to-back guarantee; replaces flat shuffle-bag approach
- Refresh JWT token for authenticated NSFW feed; add josie-hamming-2
  and dani-speegle-2 to the user list
- MultiStreamView audio focus: remove redundant isMuted writes during
  startStream and playNextWerkoutClip so audio stops ducking during
  clip transitions; gate AVAudioSession.setCategory(.playback) behind
  a one-shot flag
- GamesViewModel.attachPlayer: skip mute recalculation when the same
  player is re-attached (prevents toggle flicker on item replace)
- mlbTVOSTests target wired through project.yml with
  GENERATE_INFOPLIST_FILE; VideoShuffleTests covers groupByModel,
  pickRandomFromBuckets, real-distribution no-back-to-back invariant,
  and uniform model distribution over 6000 picks

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

README.md

@@ -0,0 +1,91 @@
+# mlbTVOS
+
+Personal MLB streaming app for Apple TV and iPhone/iPad, built with SwiftUI.
+Streams live and archived MLB games, plus a few non-MLB channels
+(MLB Network, an authenticated private feed).
+
+## Targets
+
+- `mlbTVOS` — tvOS application (primary)
+- `mlbIOS` — iOS/iPadOS application (shares most sources with the tvOS target)
+- `mlbTVOSTests` — Swift Testing unit tests
+
+The Xcode project is generated from `project.yml` via
+[XcodeGen](https://github.com/yonaskolb/XcodeGen). After editing
+`project.yml` or adding/removing source files, run:
+
+```sh
+xcodegen generate
+```
+
+## Building
+
+Requires Xcode 26.3+ and tvOS/iOS 18.0 SDKs.
+
+```sh
+# tvOS
+xcodebuild build -project mlbTVOS.xcodeproj -scheme mlbTVOS \
+  -destination 'platform=tvOS Simulator,name=Apple TV 4K (3rd generation)'
+
+# Tests
+xcodebuild test -project mlbTVOS.xcodeproj -scheme mlbTVOSTests \
+  -destination 'platform=tvOS Simulator,name=Apple TV 4K (3rd generation)'
+```
+
+## Features
+
+### Dashboard
+Today's live/scheduled/final games, standings ticker, and special channel
+entry points. Tapping a game opens the Game Center with at-bat timeline,
+pitch sequence, spray chart, and strike zone overlays.
+
+### Multi-stream view
+Up to four simultaneous streams in an adaptive grid. Only one stream holds
+audio focus at a time; tap any tile to transfer focus. Streams can be
+single broadcasts, team-filtered feeds, or special channels.
+
+### Single-stream player
+Full-screen AVPlayer with HLS adaptive streaming, custom HTTP headers,
+and automatic retry on failure.
+
+### Special playback channels
+- **MLB Network** — 24/7 channel via the public MLB stream
+- **Werkout NSFW** — authenticated private feed served by
+  [`ofapp`](https://gitea.treytartt.com) on the home server; uses a JWT
+  cookie and rotates clips through a per-model random shuffle
+
+### Video shuffle (per-model random)
+`VideoShuffle` groups clips by source folder (e.g. which model/creator
+the video came from) and picks randomly one bucket at a time, excluding
+the previously-played bucket. This guarantees **no back-to-back** same
+source and produces a roughly uniform distribution across sources even
+when one source dominates the raw data by a large factor. See
+`mlbTVOS/Services/VideoShuffle.swift` and
+`mlbTVOSTests/VideoShuffleTests.swift` for the pure functions and
+their test coverage.
+
+## Architecture
+
+- **`mlbTVOS/mlbTVOSApp.swift`** — app entry point, creates a single
+  `GamesViewModel` injected into the environment
+- **`mlbTVOS/ViewModels/GamesViewModel.swift`** — observable state store
+  for games, standings, active streams, audio focus, and video shuffle
+  bags; fetches from MLB Stats API and the auxiliary stream service
+- **`mlbTVOS/ViewModels/GameCenterViewModel.swift`** — per-game live
+  data (at-bats, pitches, box score) used by the Game Center screen
+- **`mlbTVOS/Services/`** — API clients (`MLBStatsAPI`,
+  `MLBServerAPI`) and pure helpers (`VideoShuffle`)
+- **`mlbTVOS/Views/`** — SwiftUI screens and component library
+  (`Components/AtBatTimelineView`, `PitchSequenceView`, `SprayChartView`,
+  `StrikeZoneView`, etc.)
+
+All new Swift code uses Swift 6 strict concurrency
+(`SWIFT_STRICT_CONCURRENCY: complete`).
+
+## Configuration
+
+No secret management is set up. The authenticated feed cookie is
+hardcoded in `mlbTVOS/Views/DashboardView.swift`
+(`SpecialPlaybackChannelConfig.werkoutNSFWCookie`) and must be refreshed
+manually when the JWT expires — generate a new one from the `ofapp`
+server's `jwt_secret` using the same `userId` and a longer `exp`.