feat(map): VUCC default chip, own-grid bold at all zooms, roamed-grid blue stripes

- Grid mode now opens with the VUCC award chip selected by default (re-asserted
  on every grid-mode entry; the user's in-mode chip choice is preserved).
- The station's own grid outline is now drawn at every zoom level: 2-char field
  border below the sub-square zoom, 4-char square border above it (was hidden
  at the default entry zoom), stroke widened to 6f.
- Grids the account operated from (LoTW <MY_GRIDSQUARE>, satellite QSOs only)
  are covered with GridMaster-style blue 45° zebra stripes. The stripe paint is
  fully opaque so a worked+roamed cell shows pure-blue stripes with green
  between them — the two colors never alpha-blend into a teal/green mix.
- LoTW sync now parses and persists the roamed set (LoTWResult.Success +
  SettingsRepo key 'roamedGrids'), plumbed through MapState/MapViewModel into
  MaidenheadGridOverlay. Unit tests cover MY_GRIDSQUARE parsing (SAT-only,
  GRIDSQUARE non-leak, 4-char truncation).

feature/settings/src/main/java/com/rtbishop/look4sat/feature/settings/SettingsViewModel.kt

@@ -207,6 +207,7 @@ class SettingsViewModel(
                     // synced set fully replaces the stored worked grids.
                     settingsRepo.setWorkedGrids(result.grids)
                     settingsRepo.setWorkedGridQsos(result.qsos)
+                    settingsRepo.setRoamedGrids(result.roamedGrids)
                     _uiState.update { state ->
                         state.copy(
                             lotwSyncing = false, workedGridsCount = result.grids.size,