Split web-ft.py Into Modular Backend Components

[w2naf]

Description

The current web-ft.py is a monolithic Flask application. Split it into modular components for maintainability and clarity.

Suggested Structure

• app.py — Flask app factory and configuration
• routes/ — Route handlers (API endpoints, page rendering)
• services/ — Business logic (MongoDB queries, data processing)
• utils/ — Shared utilities

Acceptance Criteria

• Backend split into logical modules
• All existing functionality preserved (no regressions)
• Import paths clean and consistent
• Dashboard fully functional after refactor

Blocked By

• Install, Test, and Debug Current DXDashboard on W3USR System #31 (Install, Test, and Debug Current DXDashboard)

Milestone

Milestone 1: Minimal Working System (Feb 28)

[w2naf]

Implementation Complete

PR: #42

What was done

Split the monolithic web-ft.py (425 lines) into modular components using Flask app factory pattern and Blueprints:

New File	Purpose
app.py	Flask app factory with DB config and blueprint registration
routes/views.py	Page routes: /, /map, /table, /display
routes/api.py	JSON API routes: /spots, /tbspots
services/spots.py	MongoDB query and data processing
services/geo.py	CQ zone GeoJSON loading and point-in-polygon lookups
utils/bands.py	frequency_to_band() utility

web-ft.py is kept as a thin 21-line wrapper so python web-ft.py and gunicorn web-ft:app still work.

Additional improvements

• Deduplicated time-query logic into shared _build_time_query() helper
• Receiver grid now configurable via RECEIVER_GRID env var with FN21ni default (prepares for Extract Receiver Callsign/Grid to Configuration #38)
• Added None guard to frequency_to_band() for missing frequency data
• Removed unused geopy and geopandas imports

Verification done

• All 6 routes register correctly
• All 4 page routes return 200 OK via Flask test client
• web-ft:app backwards compatibility confirmed
• All Python files compile without syntax errors

Notes for reviewers

• No frontend changes - all API endpoints and URL paths are unchanged
• No .env or requirements.txt changes needed
• Subsequent issues Create Shared JavaScript Config Module (config.js) #34, Extract Shared JS Utility Functions (utils.js) #35, and Extract Receiver Callsign/Grid to Configuration #38 build on this structure