feat: Add role-based API tokens for Claudia Docs

- Add api_tokens table with role-based access (researcher, developer, viewer)
- Add POST /auth/token/generate endpoint for creating tokens
- Add GET /auth/tokens endpoint for listing user's tokens
- Add DELETE /auth/tokens/{token_id} endpoint for revoking tokens
- Add agent_type field to documents (research, development, general)
- Implement role-based access control for documents:
  - researcher: access to research and general documents
  - developer: access to development and general documents
  - viewer: read-only access
- Update document model and schemas with agent_type field
- Add comprehensive tests for API token functionality
- All existing tests pass (73 total)

app/database.py

@@ -192,7 +192,8 @@ def _create_schema(sync_conn):
             model_source TEXT,
             tiptap_content TEXT,
             outgoing_links TEXT DEFAULT '[]',
-            backlinks_count INTEGER NOT NULL DEFAULT 0
+            backlinks_count INTEGER NOT NULL DEFAULT 0,
+            agent_type TEXT DEFAULT 'general' CHECK (agent_type IN ('research', 'development', 'general'))
         )
     """))
 
@@ -244,6 +245,19 @@ def _create_schema(sync_conn):
         )
     """))
 
+    # API tokens table (role-based)
+    sync_conn.execute(text("""
+        CREATE TABLE IF NOT EXISTS api_tokens (
+            id TEXT PRIMARY KEY,
+            name TEXT NOT NULL,
+            token_hash TEXT NOT NULL,
+            role TEXT NOT NULL CHECK (role IN ('researcher', 'developer', 'viewer')),
+            agent_id TEXT NOT NULL REFERENCES agents(id) ON DELETE CASCADE,
+            created_at TIMESTAMP NOT NULL DEFAULT (datetime('now')),
+            last_used_at TIMESTAMP NULL
+        )
+    """))
+
     # Indexes
     sync_conn.execute(text("CREATE INDEX IF NOT EXISTS idx_projects_agent ON projects(agent_id)"))
     sync_conn.execute(text("CREATE INDEX IF NOT EXISTS idx_folders_project ON folders(project_id)"))
@@ -254,6 +268,7 @@ def _create_schema(sync_conn):
     sync_conn.execute(text("CREATE INDEX IF NOT EXISTS idx_document_tags_tag ON document_tags(tag_id)"))
     sync_conn.execute(text("CREATE INDEX IF NOT EXISTS idx_refresh_tokens_hash ON refresh_tokens(token_hash)"))
     sync_conn.execute(text("CREATE INDEX IF NOT EXISTS idx_refresh_tokens_user_family ON refresh_tokens(user_id, token_family_id)"))
+    sync_conn.execute(text("CREATE INDEX IF NOT EXISTS idx_api_tokens_agent ON api_tokens(agent_id)"))
 
     # --- FTS5 virtual table ---
     sync_conn.execute(text("""