refactor: rename package fabledassistant -> scribe (code-only)

Renames src/fabledassistant -> src/scribe and all imports, plus the
default DB name and DB user/password (fabled -> scribe) in config +
compose. 952 refs / 154 files. Reverses the old 'internal name stays
fabledassistant' convention.

Code-only: live databases are still physically named 'fabledassistant'.
Deployed environments must set POSTGRES_DB / POSTGRES_USER (or rename the
DB) since the defaults now resolve to 'scribe'. Repo (FabledScribe), git
host (fabledsword), MCP (fabled-git) and the image name (fabledscribe)
are intentionally unchanged.

ruff check src/ clean locally; CI (typecheck + pytest) is the gate.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

scripts/import_fabledrulebook.py

@@ -103,7 +103,7 @@ async def run(args) -> None:
                 print(f"    - {r['title']}: {preview}{empty_flag}")
         return
 
-    from fabledassistant.services import rulebooks as rb_service
+    from scribe.services import rulebooks as rb_service
 
     existing = await rb_service.find_rulebook_by_title(args.user_id, args.rulebook_title)
     if existing is not None and not args.force: