refactor: move game-specific import logic into profiles; unblock Tomie import

- Add app/games: GameProfile base, registry, ReaderHooks and renpy/naninovel/
  tomie profiles. pipeline, preflight, detect and mods dispatch via the registry
- Move tomie_* converter modules to app/games/tomie and split out reader hooks,
  import, mod validation and known defects
- Tolerate the 31 authoring defects of the pinned Tomie build as report
  warnings (exact list, per-script counts); any new defect still blocks import
- Frontend: runtime registry (runtimes.ts) with lazy Tomie launcher
- Add profile/registry tests and docs/GAME_PROFILES.md; update IMPORT.md

Full media export of the original Tomie build is not yet verified.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

backend/app/games/registry.py

@@ -0,0 +1,45 @@
+"""Profile lookup. Specific (build-pinned) profiles are tried before engine-wide ones."""
+from __future__ import annotations
+
+from pathlib import Path
+
+from app.games.base import GameProfile
+
+_PROFILES: list[GameProfile] = []
+
+
+def register(profile: GameProfile) -> GameProfile:
+    if any(p.id == profile.id for p in _PROFILES):
+        raise ValueError(f"Профиль уже зарегистрирован: {profile.id}")
+    _PROFILES.append(profile)
+    return profile
+
+
+def all_profiles() -> list[GameProfile]:
+    _load()
+    return list(_PROFILES)
+
+
+def select(engine: str, root: Path) -> GameProfile | None:
+    """The profile that imports the game at ``root`` for a detected ``engine``."""
+    _load()
+    candidates = [p for p in _PROFILES if p.engine == engine]
+    for profile in sorted(candidates, key=lambda p: not p.specific):
+        if profile.claims(root):
+            return profile
+    return None
+
+
+def for_runtime(runtime: str | None) -> GameProfile | None:
+    _load()
+    return next((p for p in _PROFILES if runtime and p.runtime == runtime), None)
+
+
+def for_id(profile_id: str | None) -> GameProfile | None:
+    _load()
+    return next((p for p in _PROFILES if p.id == profile_id), None)
+
+
+def _load() -> None:
+    # Importing the package registers the built-in profiles.
+    import app.games  # noqa: F401