Add SQLite project database + ComfyUI connector nodes

- db.py: ProjectDB class with SQLite schema (projects, data_files,
  sequences, history_trees), WAL mode, CRUD, import, and query helpers
- api_routes.py: REST API endpoints on NiceGUI/FastAPI for ComfyUI
  to query project data over the network
- project_loader.py: ComfyUI nodes (ProjectLoaderDynamic, Standard,
  VACE, LoRA) that fetch data from NiceGUI REST API via HTTP
- web/project_dynamic.js: Frontend JS for dynamic project loader node
- tab_projects_ng.py: Projects management tab in NiceGUI UI
- state.py: Added db, current_project, db_enabled fields
- main.py: DB init, API route registration, projects tab
- utils.py: sync_to_db() dual-write helper
- tab_batch_ng.py, tab_raw_ng.py, tab_timeline_ng.py: dual-write
  sync calls after save_json when project DB is enabled
- __init__.py: Merged project node class mappings
- tests/test_db.py: 30 tests for database layer
- tests/test_project_loader.py: 17 tests for ComfyUI connector nodes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

api_routes.py

@@ -0,0 +1,67 @@
+"""REST API endpoints for ComfyUI to query project data from SQLite.
+
+All endpoints are read-only. Mounted on the NiceGUI/FastAPI server.
+"""
+
+import logging
+from typing import Any
+
+from fastapi import HTTPException, Query
+from nicegui import app
+
+from db import ProjectDB
+
+logger = logging.getLogger(__name__)
+
+# The DB instance is set by register_api_routes()
+_db: ProjectDB | None = None
+
+
+def register_api_routes(db: ProjectDB) -> None:
+    """Register all REST API routes with the NiceGUI/FastAPI app."""
+    global _db
+    _db = db
+
+    app.add_api_route("/api/projects", _list_projects, methods=["GET"])
+    app.add_api_route("/api/projects/{name}/files", _list_files, methods=["GET"])
+    app.add_api_route("/api/projects/{name}/files/{file_name}/sequences", _list_sequences, methods=["GET"])
+    app.add_api_route("/api/projects/{name}/files/{file_name}/data", _get_data, methods=["GET"])
+    app.add_api_route("/api/projects/{name}/files/{file_name}/keys", _get_keys, methods=["GET"])
+
+
+def _get_db() -> ProjectDB:
+    if _db is None:
+        raise HTTPException(status_code=503, detail="Database not initialized")
+    return _db
+
+
+async def _list_projects() -> dict[str, Any]:
+    db = _get_db()
+    projects = db.list_projects()
+    return {"projects": [p["name"] for p in projects]}
+
+
+async def _list_files(name: str) -> dict[str, Any]:
+    db = _get_db()
+    files = db.list_project_files(name)
+    return {"files": [{"name": f["name"], "data_type": f["data_type"]} for f in files]}
+
+
+async def _list_sequences(name: str, file_name: str) -> dict[str, Any]:
+    db = _get_db()
+    seqs = db.list_project_sequences(name, file_name)
+    return {"sequences": seqs}
+
+
+async def _get_data(name: str, file_name: str, seq: int = Query(default=1)) -> dict[str, Any]:
+    db = _get_db()
+    data = db.query_sequence_data(name, file_name, seq)
+    if data is None:
+        raise HTTPException(status_code=404, detail="Sequence not found")
+    return data
+
+
+async def _get_keys(name: str, file_name: str, seq: int = Query(default=1)) -> dict[str, Any]:
+    db = _get_db()
+    keys, types = db.query_sequence_keys(name, file_name, seq)
+    return {"keys": keys, "types": types}