chore: remove whopixels — superseded by the who module

Standalone games/whopixels has been replaced by the who module that
landed in the previous four commits. The whopixels Phaser RPG world
wrapper around the chat (~80% of the source) was deliberately
dropped during the port; the chat loop, the 26 historical-figure
personalities, and the [IDENTITY_REVEALED] sentinel trick all live
on inside apps/api/src/modules/who/.

What's gone in this commit:

  games/whopixels/                    — 33 source files, ~3.6k LOC
    Phaser scenes (Boot, MainMenu, Game, RPG)
    Managers (Player, NPC, World, Touch, Sound, Storage, ChatUI)
    Vanilla http server with hand-rolled rate limit + Azure OpenAI
    Static assets, css, jsconfig

  docker-compose.macmini.yml          — `whopixels` service block
    Build context, Azure OpenAI env wiring, healthcheck. Port 5100
    is now free. Comment left in place explaining the migration so
    a future reader doesn't wonder why this gap exists.

What still has to happen outside this PR (Mac Mini side):
  - docker rm -f mana-game-whopixels
  - cloudflared route for whopixels.mana.how needs a redirect or
    archive (sub-domain stops resolving once the container is gone
    unless DNS / tunnel routes are touched separately)

The migration is non-destructive in terms of data: whopixels stored
no per-user state — sessions were in-memory, conversation history
lived only in the browser tab. There's nothing to migrate.

Net delta of the entire who module migration (5 commits combined):
  +1880 LOC (RFC + backend + module + UI + branding)
  -3666 LOC (whopixels)
  ───────
  -1786 LOC

Closes Phase A.6 of docs/WHO_MODULE.md.

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

docker-compose.macmini.yml

@@ -1444,28 +1444,10 @@ services:
   # ============================================
   # Games
   # ============================================
-
-  whopixels:
-    build:
-      context: .
-      dockerfile: games/whopixels/Dockerfile
-    container_name: mana-game-whopixels
-    restart: unless-stopped
-    mem_limit: 128m
-    environment:
-      PORT: 5100
-      AZURE_OPENAI_API_KEY: ${AZURE_OPENAI_API_KEY:-}
-      AZURE_OPENAI_ENDPOINT: ${AZURE_OPENAI_ENDPOINT:-}
-      AZURE_OPENAI_DEPLOYMENT: ${AZURE_OPENAI_DEPLOYMENT:-}
-      AZURE_OPENAI_API_VERSION: ${AZURE_OPENAI_API_VERSION:-}
-    ports:
-      - "5100:5100"
-    healthcheck:
-      test: ["CMD", "wget", "-q", "--spider", "http://localhost:5100/"]
-      interval: 180s
-      timeout: 10s
-      retries: 3
-      start_period: 45s
+  # whopixels was removed 2026-04-09 — its core mechanic (LLM-driven
+  # historical figure guessing) lives now as the `who` module inside
+  # apps/mana/apps/web. The standalone Phaser/Node container is gone;
+  # see docs/WHO_MODULE.md for the migration rationale.
 
 volumes:
   redis_data: