feat: add ReconConfig API and UI for managing configurations

- Added a new API endpoint for managing ReconConfigs at /api/configs, including GET, POST, PUT, and a test URL feature.
- Implemented a new configuration editor UI at /configs for creating and editing ReconConfigs.
- Introduced a new configs list page at /configs to display existing configurations with options to edit.
- Updated base HTML template to include a link to the new configs page.
- Created stub configuration and authentication models for workspace development.
- Added a stub configuration module to handle database configuration without a real database.

app/models/recon_auth.py

@@ -0,0 +1,7 @@
+"""Stub auth model for workspace — production version lives in the real repo."""
+from pydantic import BaseModel
+
+
+class UserResponse(BaseModel):
+    username: str
+    email: str = ""