add mapped drives card

Mapped drives existed only as a comma-joined line in the user context card, which is fine for three drives and unreadable for a dozen. They now get their own list card in Monitors: one row per letter, remote path as meta, health as a badge. Reuses the statecolor/levels vocabulary the tracked-services cards already declare rather than new CSS. Only unhealthy drives are coloured. Green on every working drive makes the broken one just another badge in a row of badges, and the card exists to make the exception findable at a glance. Unhealthy rows sort first for the same reason - a user with a dozen mappings should not hunt for the broken one - and the sort is on health alone, so drive-letter order survives within each group and the list does not reshuffle between refreshes. The merge logic is untouched. _mapped_drive_rows now returns structured rows and the user-context summary line is built from them, so the card and the line cannot drift apart about a drive's status. The two silent-failure paths are mutation-tested: forcing every badge green failed 7 tests, and the first sort test passed a mutation that added a secondary key because every broken drive in it said the same word - it now uses statuses that would reorder under a text sort. Also corrects a stale warning claiming the merge is untested; it has been covered since Phase 1.

tests/test_plugins/test_endpoints_plugin.py

@@ -69,7 +69,7 @@ def test_endpoints_asset_panels_are_computer_scoped():
     """Every asset panel targets computer assets only, with an endpoint."""
     plugin = EndpointsPlugin()
     panels = plugin.get_asset_panels()
-    assert len(panels) == 12
+    assert len(panels) == 13
     for panel in panels:
         assert panel['assettypes'] == ['computer']
         assert panel['endpoint'].startswith('/api/endpoints/')