Add sources and citations API (Phase 1: sources-first spine)

Source CRUD (reusable, tree-scoped) and Citation create/list/soft-delete linking one source to exactly one fact (person/event/name/relationship). Editor-gated writes, privacy-filtered reads, audit throughout; tenant + existence validation on source and target. list_citations returns all tree citations so the UI can render 'sourced' indicators in one round-trip. 22 tests pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Justin Paul <justin@jpaul.me>

backend/app/services/source_service.py

@@ -0,0 +1,112 @@
+"""Source service. Sources are reusable, tree-scoped records of an origin.
+Writes require editor rights; reads go through the privacy engine."""
+
+import uuid
+from datetime import UTC, datetime
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.source import Source
+from app.models.tree import Tree
+from app.models.user import User
+from app.services import privacy
+from app.services.audit import record_audit
+from app.services.exceptions import Forbidden, NotFound
+
+
+async def create_source(
+    session: AsyncSession,
+    *,
+    actor: User,
+    tree: Tree,
+    title: str,
+    author: str | None = None,
+    source_type: str | None = None,
+    repository: str | None = None,
+    url: str | None = None,
+    citation_text: str | None = None,
+    publication_info: str | None = None,
+    quality_note: str | None = None,
+) -> Source:
+    if not await privacy.can_edit_tree(session, user_id=actor.id, tree=tree):
+        raise Forbidden("not an editor of this tree")
+    source = Source(
+        tree_id=tree.id,
+        title=title,
+        author=author,
+        source_type=source_type,
+        repository=repository,
+        url=url,
+        citation_text=citation_text,
+        publication_info=publication_info,
+        quality_note=quality_note,
+    )
+    session.add(source)
+    await session.flush()
+    record_audit(
+        session,
+        action="create",
+        entity_type="Source",
+        entity_id=source.id,
+        tree_id=tree.id,
+        actor_user_id=actor.id,
+        after={"title": title},
+    )
+    await session.commit()
+    await session.refresh(source)
+    return source
+
+
+async def list_sources(session: AsyncSession, *, viewer_id: uuid.UUID, tree: Tree) -> list[Source]:
+    if not await privacy.can_view_tree(session, user_id=viewer_id, tree=tree):
+        raise Forbidden("not permitted to view this tree")
+    stmt = (
+        select(Source)
+        .where(Source.tree_id == tree.id, Source.deleted_at.is_(None))
+        .order_by(Source.title)
+    )
+    return list((await session.execute(stmt)).scalars().all())
+
+
+async def get_source(
+    session: AsyncSession, *, viewer_id: uuid.UUID, tree: Tree, source_id: uuid.UUID
+) -> Source:
+    if not await privacy.can_view_tree(session, user_id=viewer_id, tree=tree):
+        raise Forbidden("not permitted to view this tree")
+    source = (
+        await session.execute(
+            select(Source).where(
+                Source.id == source_id, Source.tree_id == tree.id, Source.deleted_at.is_(None)
+            )
+        )
+    ).scalar_one_or_none()
+    if source is None:
+        raise NotFound("source not found")
+    return source
+
+
+async def delete_source(
+    session: AsyncSession, *, actor: User, tree: Tree, source_id: uuid.UUID
+) -> None:
+    if not await privacy.can_edit_tree(session, user_id=actor.id, tree=tree):
+        raise Forbidden("not an editor of this tree")
+    source = (
+        await session.execute(
+            select(Source).where(
+                Source.id == source_id, Source.tree_id == tree.id, Source.deleted_at.is_(None)
+            )
+        )
+    ).scalar_one_or_none()
+    if source is None:
+        raise NotFound("source not found")
+    source.deleted_at = datetime.now(UTC)
+    record_audit(
+        session,
+        action="delete",
+        entity_type="Source",
+        entity_id=source.id,
+        tree_id=tree.id,
+        actor_user_id=actor.id,
+    )
+    await session.commit()