Add Planar Capture System implementation checklist and developer reference

- Created a comprehensive implementation checklist for the Planar Capture System (Systems 136-147) detailing tasks across multiple phases including C++ core, material foundation, Blueprint actors, data assets, integration, and performance testing.
- Added a developer reference document outlining the architecture, data flow, state machine, budget enforcement, render target pooling, horror features, integration points, multiplayer networking, performance characteristics, debugging methods, and build order for the capture systems.
- Introduced examples of capture surface usage in the Project Void horror game, including specific implementations for mirrors, monitors, portals, and fake windows, along with a checklist for integration tasks.

docs/game/GAMEINDEX.md

@@ -199,8 +199,21 @@ Content/Game/                              ← ALL game content (NEVER modify Fr
 │   ├── BP_LightEvent_Flicker.uasset
 │   ├── BP_ScareEvent_LockerBang.uasset
 │   ├── BP_ScareEvent_Mirror.uasset
+│   ├── BP_HorrorMirror_Morgue.uasset        ← Horror mirror (wrong reflection scare)
+│   ├── BP_Mirror_NurseStation.uasset        ← Standard mirror (checkpoint reflection)
 │   └── BP_AtmosphereController_WardA.uasset
 │
+├── Capture/                                 ← Planar Capture surface actors
+│   ├── BP_Mirror_NurseStation.uasset        ← Standard mirror: Mode=Mirror, aged, checkpoint
+│   ├── BP_HorrorMirror_Morgue.uasset        ← Horror mirror: wrong reflection, steam scare
+│   ├── BP_HorrorMirror_WardensOffice.uasset ← Horror mirror: final entity confrontation
+│   ├── BP_Monitor_Security.uasset           ← Security monitor: hallway camera feed, scanlines
+│   ├── BP_Monitor_Morgue.uasset             ← Morgue monitor: static noise, flicker, Shade cameo
+│   ├── BP_Portal_VoidEntrance.uasset        ← Void portal entrance (Basement → VoidSpace)
+│   ├── BP_Portal_VoidExit.uasset            ← Void portal exit (VoidSpace → Basement)
+│   ├── BP_FakeWindow_WardensOffice.uasset   ← Atmospheric window: rain, night, parallax
+│   └── DA_PlanarCaptureProfile_Mirror.uasset← Capture profile Data Assets
+│
 ├── Audio/                                  ← Game-specific audio assets
 │   ├── DA_AudioSettings_Horror.uasset     ← Audio bus config
 │   ├── BP_RoomAudioZone_WardA.uasset      ← Room audio zone volumes
@@ -600,6 +613,22 @@ Each game asset proves a specific framework system works. Below: every framework
 | 130 | BPC_StateManager | Hiding blocks fire; death blocks interaction; cutscene blocks all |
 | 131 | DA_StateGatingTable | Designer-configurable state permission rules |
 
+### 17-capture (Planar Capture — 12 systems)
+| # | Framework System | Demonstrated By |
+|---|-----------------|----------------|
+| 136 | BPC_PlanarCapture | All capture surfaces (component managing SceneCapture2D lifecycle) |
+| 137 | BP_PlanarCaptureActor | BP_Mirror, BP_Portal, BP_Monitor, BP_HorrorMirror, BP_FakeWindow (all extend this) |
+| 138 | SS_PlanarCaptureManager | Auto-created WorldSubsystem — manages quality budget across all 8 surfaces |
+| 139 | BP_Mirror | BP_Mirror_NurseStation — standard reflection mirror with aging |
+| 140 | BP_Portal | BP_Portal_VoidEntrance/Exit — void portal teleport with clip plane |
+| 141 | BP_Monitor | BP_Monitor_Security/Morgue — security camera feeds, scanlines, static noise |
+| 142 | BP_HorrorMirror | BP_HorrorMirror_Morgue/WardensOffice — wrong reflection, steam, text, scare events |
+| 143 | BP_FakeWindow | BP_FakeWindow_WardensOffice — atmospheric window with weather overlay |
+| 144 | M_CaptureSurface_Master | All mirror/portal/monitor surfaces (9-layer material stack) |
+| 145 | MPC_CaptureSurface | All 10 MPC scalar params (SteamIntensity, DirtOpacity, MirrorDarkness, etc.) |
+| 146 | DA_PlanarCaptureProfile | DA_PlanarCaptureProfile_Mirror — per-surface quality config |
+| 147 | MI_MirrorInstances | MI_Mirror_Clean/Dirty/Steam/Horror, MI_Portal_Standard, MI_Monitor_Security, MI_FakeWindow_Interior |
+
 ---
 
 ## Build Order (Dependency-Safe)
@@ -625,7 +654,8 @@ Follow this order when creating uasset files in UE5:
 | 14 | **Data Assets (Content)** — Encounters, Atmosphere, Scares, Puzzles, Objectives, Behaviour, Acoustic | DA_* parents | 20+ |
 | 15 | **Checkpoints** — BP_Checkpoint_SafeRoom, _Mirror | BP_Checkpoint | 2 |
 | 16 | **Room Audio Zones** — BP_RoomAudioZone_* | BP_RoomAudioZone | 3 |
-| 17 | **Encounter Spawners** — BP_EncounterSpawner_* | BPC_ProceduralEncounter | 3 |
+| 17 | **Capture Surfaces** — BP_Mirror_NurseStation, BP_HorrorMirror_Morgue/WardensOffice, BP_Monitor_Security/Morgue, BP_Portal_VoidEntrance/Exit, BP_FakeWindow_WardensOffice | BP_PlanarCaptureActor | 9 |
+| 18 | **Encounter Spawners** — BP_EncounterSpawner_* | BPC_ProceduralEncounter | 3 |
 | 18 | **Atmosphere Actors** — BP_LightEvent_*, BP_ScareEvent_*, BP_AtmosphereController_* | BPC_* parent | 6 |
 | 19 | **Tutorial Triggers** — BP_TutorialTrigger_* | BPC_TutorialSystem | 3 |
 | 20 | **Polish** — BP_CreditsSequence, dev cheats, debug menu | Framework | 3 |
@@ -657,6 +687,7 @@ Each `docs/game/` file explains how to build a specific section of the prototype
 | [`enemies-index.md`](enemies-index.md) | All enemies — Patient, Shade, Orderly — AI controllers, BT, perception | 12 |
 | [`narrative-progression.md`](narrative-progression.md) | Objectives, dialogue, cutscenes, ending accumulator, branching | 13 |
 | [`atmosphere-audio.md`](atmosphere-audio.md) | Atmosphere profiles, scares, lighting, room audio zones, adaptive environment | 14, 16, 17, 18 |
+| [`planar-capture-examples.md`](planar-capture-examples.md) | Mirrors, horror mirrors, security monitors, void portals, fake windows — all 8 capture surfaces | 17 |
 | [`save-checkpoints.md`](save-checkpoints.md) | Save system, checkpoints, death loop, void space, persistence | 15 |
 | [`polish-loading-credits.md`](polish-loading-credits.md) | Tutorials, loading screen, credits, debug, analytics | 19, 20 |
 | [`state-gating-examples.md`](state-gating-examples.md) | DA_StateGatingTable game-specific rules | 14 |