feat(alpha): wire connect→snapshot→disconnect end-to-end (v0.1.0-alpha.1)

First Internal Alpha build per DEC-001. Closes the milestone of
'Flutter UI calls Rust via the typed bridge, Rust connects to a
TeamSpeak-compatible server through tsclientlib, returns a typed
snapshot, and disconnects cleanly.' Audio remains Beta scope.

Promotions from PoC:
  poc/tsclientlib-connect-spike  →  crates/chanora_protocol/

New product code:
  crates/chanora_protocol/src/{dto.rs,adapter.rs} — typed boundary
    over tsclientlib. Tokio task owns the Connection; public
    handle communicates via mpsc/oneshot. No tsclientlib types
    cross out of the crate (SAD-067 / SysDes-011 / SysDes-029).
  core/chanora_core/src/lib.rs — ChanoraSession composes the
    protocol crate, enforces the DEC-006 single-connection
    invariant.
  crates/chanora_bridge/src/{api.rs,frb_generated.rs} — FRB 2.12.0
    bridge per DEC-014. cdylib + staticlib + rlib. Typed
    BridgeSnapshot / BridgeChannel / BridgeClient / BridgeError
    DTOs. Process-wide OnceLock<Runtime> + OnceLock<ChanoraSession>.
  flutter_rust_bridge.yaml at repo root.
  apps/chanora_flutter/lib/main.dart — Alpha UI: server form,
    connect button, channel tree, disconnect.
  apps/chanora_flutter/lib/l10n/app_{en,zh}.arb expanded with the
    Alpha key set; ARB metadata reaffirms ADR-008 for
    server-provided content.
  Generated Dart bindings under apps/chanora_flutter/lib/src/rust/.

Empirical verification (2026-05-14):
  Workspace: cargo check + cargo test clean
    (workspace tests: all green).
  Bridge cdylib: target/release/libchanora_bridge.so produced
    (~15 MB).
  Flutter: flutter analyze clean; flutter test runs 3/3 green
    including the alpha_e2e_test that drives the full
      Dart → FRB → chanora_bridge → chanora_core → chanora_protocol
        → tsclientlib → UDP → cn.teamspeak.app
    path. The captured logcat/stdout shows the tsproto resender
    transitioning Connected → Disconnecting → Disconnected on
    clean teardown.

Architecture changes:
  - Removed the chanora_core ↔ chanora_bridge cyclic dependency.
    chanora_core no longer knows the bridge exists; the bridge
    maps from CoreError.
  - chanora_bridge crate's #![forbid(unsafe_code)] lint relaxed
    because FRB-generated glue legitimately uses unsafe at the
    FFI boundary. Hand-written code remains unsafe-free.

Open follow-ups (NOT in this Alpha):
  - Audio capture/playback wiring into chanora_audio
    (Beta scope per DEC-001).
  - Identity persistence via chanora_storage
    (currently regenerated on every connect).
  - Per-message diagnostics + redaction
    (chanora_diagnostics still scaffold).
  - Reconnect / network-loss recovery.
  - Mobile (Android) build of the bridge cdylib + UI verification.

apps/chanora_flutter/lib/src/rust/api.dart

@@ -0,0 +1,147 @@
+// This file is automatically generated, so please do not edit it.
+// @generated by `flutter_rust_bridge`@ 2.12.0.
+
+// ignore_for_file: invalid_use_of_internal_member, unused_import, unnecessary_import
+
+import 'frb_generated.dart';
+import 'lib.dart';
+import 'package:flutter_rust_bridge/flutter_rust_bridge_for_generated.dart';
+
+// These functions are ignored because they are not marked as `pub`: `runtime`, `session`
+// These function are ignored because they are on traits that is not defined in current crate (put an empty `#[frb]` on it to unignore): `clone`, `clone`, `clone`, `fmt`, `fmt`, `fmt`, `from`
+
+/// Connect to a TeamSpeak-compatible server and return the initial
+/// state snapshot. Honours the DEC-006 single-connection invariant
+/// via [`BridgeError::AlreadyConnected`].
+Future<BridgeSnapshot> connect({
+  required String host,
+  required String nickname,
+}) => RustLib.instance.api.crateApiConnect(host: host, nickname: nickname);
+
+/// Re-fetch a fresh snapshot from the active connection.
+Future<BridgeSnapshot> snapshot() => RustLib.instance.api.crateApiSnapshot();
+
+/// Disconnect from the server. No-op if not connected.
+Future<void> disconnect() => RustLib.instance.api.crateApiDisconnect();
+
+/// True if a connection is currently active.
+Future<bool> isConnected() => RustLib.instance.api.crateApiIsConnected();
+
+/// Channel as seen by Dart. Matches `chanora_protocol::ChannelInfo`
+/// but with primitive `u64` ids so the Dart side gets `BigInt`s
+/// without any wrapper-type ceremony.
+class BridgeChannel {
+  /// Stable channel id.
+  final BigInt id;
+
+  /// Parent channel id; 0 means top-level.
+  final BigInt parent;
+
+  /// Display name.
+  final String name;
+
+  /// Server-side ordering hint.
+  final PlatformInt64 order;
+
+  const BridgeChannel({
+    required this.id,
+    required this.parent,
+    required this.name,
+    required this.order,
+  });
+
+  @override
+  int get hashCode =>
+      id.hashCode ^ parent.hashCode ^ name.hashCode ^ order.hashCode;
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      other is BridgeChannel &&
+          runtimeType == other.runtimeType &&
+          id == other.id &&
+          parent == other.parent &&
+          name == other.name &&
+          order == other.order;
+}
+
+/// Client as seen by Dart.
+class BridgeClient {
+  /// Stable client id.
+  final BigInt id;
+
+  /// Channel id the client is currently in.
+  final BigInt channel;
+
+  /// Nickname.
+  final String name;
+
+  const BridgeClient({
+    required this.id,
+    required this.channel,
+    required this.name,
+  });
+
+  @override
+  int get hashCode => id.hashCode ^ channel.hashCode ^ name.hashCode;
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      other is BridgeClient &&
+          runtimeType == other.runtimeType &&
+          id == other.id &&
+          channel == other.channel &&
+          name == other.name;
+}
+
+/// Server snapshot as seen by Dart.
+class BridgeSnapshot {
+  /// Server name.
+  final String serverName;
+
+  /// Welcome banner text.
+  final String welcomeMessage;
+
+  /// Server platform (e.g. "Linux").
+  final String platform;
+
+  /// Server version string.
+  final String version;
+
+  /// Channels currently known.
+  final List<BridgeChannel> channels;
+
+  /// Clients currently known.
+  final List<BridgeClient> clients;
+
+  const BridgeSnapshot({
+    required this.serverName,
+    required this.welcomeMessage,
+    required this.platform,
+    required this.version,
+    required this.channels,
+    required this.clients,
+  });
+
+  @override
+  int get hashCode =>
+      serverName.hashCode ^
+      welcomeMessage.hashCode ^
+      platform.hashCode ^
+      version.hashCode ^
+      channels.hashCode ^
+      clients.hashCode;
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      other is BridgeSnapshot &&
+          runtimeType == other.runtimeType &&
+          serverName == other.serverName &&
+          welcomeMessage == other.welcomeMessage &&
+          platform == other.platform &&
+          version == other.version &&
+          channels == other.channels &&
+          clients == other.clients;
+}