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/group.py

@@ -0,0 +1,57 @@
+from datetime import datetime, timezone
+
+from sqlalchemy import ForeignKey, Integer, Text, UniqueConstraint
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from scribe.models import Base
+from scribe.models.base import CreatedAtMixin, TimestampMixin
+
+
+class Group(Base, TimestampMixin):
+    __tablename__ = "groups"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True)
+    name: Mapped[str] = mapped_column(Text, nullable=False, unique=True)
+    description: Mapped[str | None] = mapped_column(Text)
+    created_by: Mapped[int | None] = mapped_column(
+        Integer, ForeignKey("users.id", ondelete="SET NULL")
+    )
+
+    memberships: Mapped[list["GroupMembership"]] = relationship(
+        "GroupMembership", back_populates="group", cascade="all, delete-orphan"
+    )
+
+    def to_dict(self) -> dict:
+        return {
+            "id": self.id,
+            "name": self.name,
+            "description": self.description,
+            "created_by": self.created_by,
+            "created_at": self.created_at.isoformat(),
+            "updated_at": self.updated_at.isoformat(),
+        }
+
+
+class GroupMembership(Base, CreatedAtMixin):
+    __tablename__ = "group_memberships"
+    __table_args__ = (UniqueConstraint("group_id", "user_id", name="uq_gm_group_user"),)
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True)
+    group_id: Mapped[int] = mapped_column(
+        Integer, ForeignKey("groups.id", ondelete="CASCADE"), nullable=False
+    )
+    user_id: Mapped[int] = mapped_column(
+        Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False
+    )
+    role: Mapped[str] = mapped_column(Text, nullable=False, default="member")
+
+    group: Mapped["Group"] = relationship("Group", back_populates="memberships")
+
+    def to_dict(self) -> dict:
+        return {
+            "id": self.id,
+            "group_id": self.group_id,
+            "user_id": self.user_id,
+            "role": self.role,
+            "created_at": self.created_at.isoformat(),
+        }