- Fix Module.safe_concat -> Module.concat in tests with dynamic process names
(safe_concat calls binary_to_existing_atom, but test names are newly generated)
- Fix PSKR AggregatorTest sandbox ownership by switching to async: false
- Fix MapLiveTest assert_patch: regex unsupported in LiveView 1.2, use string match
- Fix WeatherMapLiveTest toggle_grid: assert on checked attribute, not data-grid
- Fix BeaconLive.Index leaking unapproved beacons: wire data_provider to approved_beacons_query
- Fix ContactLive.Index leaking private contacts: wire data_provider with visibility filter
- Fix RecalibratorTest: train() expects factor vectors, not {vector, datetime, band} tuples
- Fix toggle_sort: compare current_field to new_field, not current_order
- Fix internal_network?: handle both atom and string session keys from Plug sessions
Test results: 3979/4001 -> 3997/4001 (18 previously-failing tests now pass)