Refaktor 2/4: superheroji izdvojen u plugin (apps/superheroji) + AppContext

Prvi pravi mini-app kao samostalan folder:
- idriz/apps/base.py: AppSpec, AppTool, AppContext (uski most ka runtime-u).
- idriz/apps/__init__.py: load_apps() (lijeni uvoz manifesta).
- idriz/apps/superheroji/: logic.py (bivši game.py), store.py (bivši gamestore.py),
  manifest.py (prompt fragment + sheme + handleri preko ctx).

Assistant više NEMA game_* metode ni self.match: prompt/tools/pozdrav/dispatch se
grade iz registra app-ova + jezgra. Admin uvozi apps.superheroji.store (bez openai).
Ponašanje isto (testirano: mehanika, handleri kroz AppContext, admin bez openai).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LzKpYaEsuWDevuNnvSjcFW

admin/app.py

@@ -19,7 +19,7 @@ from flask import (
 
 # Pristup skladištu igre (bez openai zavisnosti) iz glavnog idriz paketa.
 sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
-from idriz import gamestore  # noqa: E402
+from idriz.apps.superheroji import store as gamestore  # noqa: E402
 
 # --- Konfiguracija -----------------------------------------------------------