feat(topology): M2 - API-driven demo page with layout tables and dynamic rendering

- Add diagram_layouts and diagram_nodes tables
- Seed layout coordinates extracted from SVG
- Extend snapshot API to return layout data
- Rewrite demo page to fetch from API dynamically
- Support ?mission= and ?at= URL parameters
- Modal details populated from database component data
- Show/hide nodes based on component existence at snapshot time

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

topology_api/app.py

@@ -1,11 +1,13 @@
 # topology_api/app.py
 from flask import Flask
+from flask_cors import CORS
 from topology_api.config import API_HOST, API_PORT, API_DEBUG
 from topology_api.routes.snapshot import snapshot_bp
 
 
 def create_app():
     app = Flask(__name__)
+    CORS(app)
     app.register_blueprint(snapshot_bp)
 
     @app.route("/health")