Full-CRUD sweep: update endpoints for tree, source, citation, relationship, media

Closes the rule #8 gap at the API layer: PATCH endpoints + service updates for Tree (name/description/visibility), Source, Citation (page/detail/confidence), Relationship (qualifier/notes), and Media (title/attachment) — editor-gated and audited. Every core entity now has create/read/update/delete. Edit UIs for these land in the frontend batch. 37 tests pass.

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

backend/app/schemas/source.py

@@ -33,6 +33,23 @@ class SourceRead(BaseModel):
     created_at: datetime
 
 
+class SourceUpdate(BaseModel):
+    title: str | None = None
+    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
+
+
+class CitationUpdate(BaseModel):
+    page: str | None = None
+    detail: str | None = None
+    confidence: CitationConfidence | None = None
+
+
 class CitationCreate(BaseModel):
     source_id: uuid.UUID
     # Exactly one target fact.