feat: import Chinese-localized Buzz source snapshot

Signed-off-by: cls_宁波本机 <908705107@qq.com>

mobile/lib/shared/relay/relay_provider.dart

@@ -0,0 +1,126 @@
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:nostr/nostr.dart' as nostr;
+
+import '../community/community_provider.dart';
+import 'relay_client.dart';
+
+/// Relay connection configuration.
+///
+/// In the pure-nostr world the only secrets the app cares about are:
+///   - `baseUrl` — where the relay lives (used for WS + media upload)
+///   - `nsec`    — the user's signing key (drives NIP-42 AUTH and event sigs)
+class RelayConfig {
+  const RelayConfig({required String baseUrl, this.nsec}) : _baseUrl = baseUrl;
+
+  /// Relay origin exactly as the active community stored it.
+  final String _baseUrl;
+
+  /// Nostr secret key (bech32 nsec) for signing events and NIP-42 AUTH.
+  final String? nsec;
+
+  /// The origin as persisted, before scheme canonicalization.
+  ///
+  /// Exists solely so identity-scoped storage keys written before [baseUrl]
+  /// was canonicalized stay reachable — see [readMigratedPref]. Never use it
+  /// for network I/O; [baseUrl] and [wsUrl] are the addresses to connect to.
+  String get storedOrigin => _baseUrl;
+
+  /// Relay origin as an HTTP(S) URL.
+  ///
+  /// Communities are persisted with whichever scheme their onboarding flow
+  /// used: device pairing stores `https://` (it rejects anything else), while
+  /// an invite join stores the `wss://` relay URL carried by the invite link.
+  /// Every consumer treats this as an HTTP origin — [wsUrl], the `/query`
+  /// endpoint, media upload and Blossom auth — so a `wss://` base silently
+  /// degrades all of them. Folding the websocket schemes back here keeps both
+  /// onboarding paths equivalent, including for already-persisted communities.
+  ///
+  /// Derived rather than normalized in the constructor so that the constructor
+  /// stays `const`: the compile-time fallback below relies on canonicalization
+  /// to keep its identity stable across rebuilds, and Riverpod's default
+  /// `updateShouldNotify` is `previous != next`, which falls back to identity
+  /// here. A fresh instance per rebuild would resubscribe every listener.
+  String get baseUrl {
+    final uri = Uri.tryParse(_baseUrl);
+    if (uri == null) return _baseUrl;
+    final scheme = switch (uri.scheme) {
+      'wss' => 'https',
+      'ws' => 'http',
+      _ => null,
+    };
+    return scheme == null ? _baseUrl : uri.replace(scheme: scheme).toString();
+  }
+
+  /// Derive the websocket URL from the HTTP base URL.
+  String get wsUrl {
+    final uri = Uri.parse(baseUrl);
+    final scheme = uri.scheme == 'https' ? 'wss' : 'ws';
+    return uri.replace(scheme: scheme).toString();
+  }
+}
+
+/// Compile-time environment config via --dart-define.
+///
+/// Run with:
+///   flutter run --dart-define=BUZZ_RELAY_URL=http://localhost:3000
+///
+/// Or create a `.env.json` and use --dart-define-from-file=.env.json
+class Env {
+  static const relayUrl = String.fromEnvironment(
+    'BUZZ_RELAY_URL',
+    defaultValue: 'http://localhost:3000',
+  );
+}
+
+class RelayConfigNotifier extends Notifier<RelayConfig> {
+  @override
+  RelayConfig build() {
+    // Watch the active community so that when it changes (community switch),
+    // the config rebuilds, triggering the full provider cascade.
+    final activeAsync = ref.watch(activeCommunityProvider);
+    final active = activeAsync.value;
+    if (active != null) {
+      return RelayConfig(baseUrl: active.relayUrl, nsec: active.nsec);
+    }
+
+    // Fallback to compile-time env config (dev mode).
+    return const RelayConfig(baseUrl: Env.relayUrl);
+  }
+
+  void update({required String baseUrl, String? nsec}) {
+    state = RelayConfig(baseUrl: baseUrl, nsec: nsec);
+  }
+}
+
+final relayConfigProvider = NotifierProvider<RelayConfigNotifier, RelayConfig>(
+  RelayConfigNotifier.new,
+);
+
+/// Derive the hex pubkey from a bech32 nsec, or null on any failure.
+String? pubkeyFromNsec(String? nsec) {
+  if (nsec == null || nsec.isEmpty) return null;
+  try {
+    final privkeyHex = nostr.Nip19.decode(payload: nsec).data;
+    if (privkeyHex.isEmpty) return null;
+    return nostr.Keys(privkeyHex).public;
+  } catch (_) {
+    return null;
+  }
+}
+
+/// The current user's hex pubkey, derived from the active community nsec.
+final myPubkeyProvider = Provider<String?>((ref) {
+  final config = ref.watch(relayConfigProvider);
+  return pubkeyFromNsec(config.nsec);
+});
+
+/// Provides a [RelayClient] that reacts to config changes.
+///
+/// Only used for the media upload HTTP endpoint now — all data flow goes
+/// through the relay WebSocket session.
+final relayClientProvider = Provider<RelayClient>((ref) {
+  final config = ref.watch(relayConfigProvider);
+  final client = RelayClient(baseUrl: config.baseUrl);
+  ref.onDispose(client.dispose);
+  return client;
+});