fix: stabilize test suite and repair frontend/backend wiring

- meshcore pin >=2.3.0 (EventType.STATS_CORE floor); setup.sh derives
  optional packages from requirements.txt; Python 3.10 warning
- agent-mode wifi clients proxy route + bare-array response handling
- remove dead AIS/ACARS/VDL2 SPA wiring and orphaned partials/CSS
- agent TLE download to data/tle/ (was littering repo root as gp.php)
- gate deferred background init off under pytest (mock-pollution race)
- complete Popen mocks (context manager protocol, communicate tuples)
- real pipe fds in weather-sat decoder tests (fd 10/11 collision caused
  10s SQLite stalls); satellite tests no longer rewrite data/satellites.py
- register 'live' pytest marker, excluded by default
- update stale test assertions to current APIs

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/test_meshcore_client.py

@@ -126,7 +126,7 @@ class TestMeshcoreClientStateMachine:
             client.get_queue().get_nowait()
         # Call on_connected directly (simulating what AsyncWorker would call)
         client.on_connected(transport="serial", device="/dev/ttyUSB0")
-        assert client.get_state() == ConnectionState.CONNECTED
+        assert client.get_state()[0] == ConnectionState.CONNECTED
         event = client.get_queue().get_nowait()
         assert event["type"] == "status"
         assert event["data"]["state"] == "connected"