Phase 1 MVP - Complete implementation

- Auth: register, login, JWT with refresh tokens, blocklist
- Projects/Folders/Documents CRUD with soft deletes
- Tags CRUD and assignment
- FTS5 search with highlights and tag filtering
- ADR-001, ADR-002, ADR-003 compliant
- Security fixes applied (JWT_SECRET_KEY, exception handler, cookie secure)
- 25 tests passing

app/schemas/tag.py

@@ -0,0 +1,25 @@
+from datetime import datetime
+
+from pydantic import BaseModel
+
+
+class TagCreate(BaseModel):
+    name: str
+    color: str = "#6366f1"
+
+
+class TagResponse(BaseModel):
+    id: str
+    name: str
+    color: str
+    created_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class TagListResponse(BaseModel):
+    tags: list[TagResponse]
+
+
+class DocumentTagsAssign(BaseModel):
+    tag_ids: list[str]