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+# Battleground UI — Task Tracker
+> Created: 2026-03-28  
+> Branch: `feat/battleground-ui`
+
+All issues below are part of the **4-player Commander Battleground** Unity 3D UI build.
+Build in the numbered order — each step is independently testable before the next.
+
+---
+
+## Build Order Checklist
+
+| # | Issue | Script(s) | Needs Backend? | Status |
+|---|-------|-----------|----------------|--------|
+| 1 | [#138 — Battleground.unity scene + 4-seat layout](https://github.com/KoalaTrapLord/commander-ai-lab/issues/138) | `BattlegroundController.cs`, `GameStateManager.cs` | No | ⬜ |
+| 2 | [#139 — LifeTrackerWidget + CommanderDamageRow + Poison](https://github.com/KoalaTrapLord/commander-ai-lab/issues/139) | `LifeTrackerWidget.cs`, `CommanderDamageRow.cs` | No | ⬜ |
+| 3 | [#140 — PhaseTrackerWidget + PhaseStepButton](https://github.com/KoalaTrapLord/commander-ai-lab/issues/140) | `PhaseTrackerWidget.cs`, `PhaseStepButton.cs` | No | ⬜ |
+| 4 | [#141 — TurnOrderBar + TurnOrderPill](https://github.com/KoalaTrapLord/commander-ai-lab/issues/141) | `TurnOrderBar.cs`, `TurnOrderPill.cs` | No | ⬜ |
+| 5 | [#142 — CardZone + CardView](https://github.com/KoalaTrapLord/commander-ai-lab/issues/142) | `CardZone.cs`, `CardView.cs` | ImageCache only | ⬜ |
+| 6 | [#143 — CommanderZoneWidget](https://github.com/KoalaTrapLord/commander-ai-lab/issues/143) | `CommanderZoneWidget.cs` + `ImageCache` art_crop | ImageCache only | ⬜ |
+| 7 | [#144 — Token System](https://github.com/KoalaTrapLord/commander-ai-lab/issues/144) | `TokenModel.cs`, `TokenPanelController.cs`, `TokenRowView.cs` | No | ⬜ |
+| 8 | [#146 — StackZoneController + ManaPoolDisplay](https://github.com/KoalaTrapLord/commander-ai-lab/issues/146) | `StackZoneController.cs`, `ManaPoolDisplay.cs` | No (events only) | ⬜ |
+| 9 | [#147 — LobbySetupModal + ZoneViewerModal](https://github.com/KoalaTrapLord/commander-ai-lab/issues/147) | `LobbySetupModal.cs`, `ZoneViewerModal.cs` | `/api/decks`, `/api/game/start` | ⬜ |
+| 10 | [#148 — GameStateManager + GameState POCOs](https://github.com/KoalaTrapLord/commander-ai-lab/issues/148) | `GameStateManager.cs`, `GameState.cs` | No | ⬜ |
+| 11 | [#149 — GameWebSocketClient](https://github.com/KoalaTrapLord/commander-ai-lab/issues/149) | `GameWebSocketClient.cs` | Yes — `/ws/game` | ⬜ |
+| 12 | [#145 — HumanActionBar](https://github.com/KoalaTrapLord/commander-ai-lab/issues/145) | `HumanActionBar.cs` | Yes — `/api/game/action` | ⬜ |
+| 13 | [#150 — EliminationHandler + Grayscale Shader](https://github.com/KoalaTrapLord/commander-ai-lab/issues/150) | `EliminationHandler.cs`, `EliminatedGrayscale` ShaderGraph | No | ⬜ |
+| 14 | [#151 — SimulationController: Play Live button](https://github.com/KoalaTrapLord/commander-ai-lab/issues/151) | `SimulationController.cs` (modify) | No | ⬜ |
+
+---
+
+## New Files Summary
+
+### `Assets/Scripts/UI/Battleground/`
+- `BattlegroundController.cs`
+- `GameStateManager.cs`
+- `LifeTrackerWidget.cs`
+- `CommanderDamageRow.cs`
+- `PhaseTrackerWidget.cs`
+- `PhaseStepButton.cs`
+- `TurnOrderBar.cs`
+- `TurnOrderPill.cs`
+- `CardZone.cs`
+- `CardView.cs`
+- `CommanderZoneWidget.cs`
+- `TokenPanelController.cs`
+- `TokenRowView.cs`
+- `StackZoneController.cs` + `StackItemView.cs`
+- `ManaPoolDisplay.cs`
+- `LobbySetupModal.cs`
+- `ZoneViewerModal.cs`
+- `HumanActionBar.cs`
+- `EliminationHandler.cs`
+
+### `Assets/Scripts/Models/`
+- `TokenModel.cs` (new)
+- `GameState.cs` (new — `GameState`, `SeatState` POCOs)
+
+### `Assets/Scripts/Services/`
+- `GameWebSocketClient.cs` (new)
+
+### `Assets/Scenes/`
+- `Battleground.unity` (new scene)
+
+### `Assets/Materials/`
+- `EliminatedGrayscale` (URP Shader Graph)
+
+### Modified
+- `Assets/Scripts/UI/SimulationController.cs` — add Play Live button
+- `Assets/Scripts/UI/MainMenuController.cs` — add Play Live nav button
+- `Assets/Scripts/Services/ImageCache.cs` — add `LoadArtCrop()` method
+- `Assets/Scripts/Models/CardModel.cs` — add `[NonSerialized]` runtime battleground state fields
+
+---
+
+## Architecture Notes
+
+- **`GameStateManager`** is the singleton event hub — all UI widgets subscribe to its events, never poll
+- **`GameWebSocketClient`** receives server push messages and routes them to `GameStateManager.ApplyServerEvent()`
+- **Canvas mode**: Screen Space — Camera (not World Space) for crisp TMP rendering
+- **Seat rotation**: AI panels rotated -90°, 180°, 90° via `localEulerAngles` so text/buttons face the right direction
+- **Backend WS**: connect to `ws://localhost:8080/ws/game` (configurable via `PlayerPrefs["ServerUrl"]`)