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>

src/scribe/models/embedding.py

@@ -0,0 +1,25 @@
+from datetime import datetime, timezone
+
+from sqlalchemy import DateTime, ForeignKey, Integer
+from sqlalchemy.dialects.postgresql import JSONB
+from sqlalchemy.orm import Mapped, mapped_column
+
+from scribe.models import Base
+
+
+class NoteEmbedding(Base):
+    """Stores the embedding vector for a note, used for semantic search."""
+
+    __tablename__ = "note_embeddings"
+
+    note_id: Mapped[int] = mapped_column(
+        Integer,
+        ForeignKey("notes.id", ondelete="CASCADE"),
+        primary_key=True,
+    )
+    user_id: Mapped[int] = mapped_column(Integer, nullable=False, index=True)
+    embedding: Mapped[list] = mapped_column(JSONB, nullable=False)
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        default=lambda: datetime.now(timezone.utc),
+    )