fix(block2): sharing config UX + discovery + labels (raw feedback batch)

From on-device feedback:
- Area is no longer shown as a raw geohash 'name'. 'Use my location' is the
  primary action; a human status line says whether your area is set (coarse,
  never exact). The geohash code + the relay servers moved under 'Advanced'
  (code field labelled 'a code like sp3e9 — not a place name'), which also
  brings back node/relay selection that had been fully hidden.
- Location denial no longer yanks you into system settings — returns quietly
  with an actionable inline message.
- Discovery no longer spins forever when nobody's sharing nearby: a timeout
  resolves 'searching' to the empty state.
- Home card 'Open market' -> 'Market' + 'Discover and share seeds nearby'
  (the word 'open' confused).

i18n en/es/pt; analyzer clean; the use-my-location test asserts the status flip.

apps/app_seeds/lib/i18n/strings.g.dart

@@ -4,9 +4,9 @@
 /// To regenerate, run: `dart run slang`
 ///
 /// Locales: 3
-/// Strings: 1043 (347 per locale)
+/// Strings: 1058 (352 per locale)
 ///
-/// Built on 2026-07-10 at 11:05 UTC
+/// Built on 2026-07-10 at 11:31 UTC
 
 // coverage:ignore-file
 // ignore_for_file: type=lint, unused_import