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.

crates/chanora_bridge/src/lib.rs

@@ -1,42 +1,73 @@
 //! # `chanora_bridge`
 //!
-//! Typed Flutter/Rust bridge. Owns the canonical DTO catalogue for
-//! commands (Dart → Rust), results (Rust → Dart return values), and
-//! events (Rust → Dart streams).
+//! Typed Flutter/Rust bridge — schema-controlled DTOs for commands,
+//! results, and events. Backed by `flutter_rust_bridge` 2.x per
+//! DEC-014.
 //!
-//! Bridge tool per DEC-014: `flutter_rust_bridge` 2.x. The bridge
-//! integration glue (codegen invocations, the cdylib boundary) is
-//! added when `apps/chanora_flutter` is wired up; this crate owns
-//! only the type definitions and error mappings — explicitly *not*
-//! `tsclientlib` or raw subsystem types (SAD-067, SDD-079).
+//! ## Alpha scope
 //!
-//! ## Status
+//! Exposes three commands that target the Alpha release goal:
 //!
-//! Scaffold only.
+//! * `bridge_init()` — one-time process initialisation. Sets up
+//!   logging.
+//! * `connect(host, nickname)` — connects to a TS3-compatible
+//!   server and returns a typed [`ConnectResultDto`] containing the
+//!   server snapshot.
+//! * `disconnect()` — clean disconnect.
+//! * `snapshot()` — re-fetch the current server snapshot.
+//!
+//! No audio commands cross the bridge in Alpha; audio is Beta scope.
+//!
+//! ## Boundary discipline
+//!
+//! Every type in this module is `Serialize + Deserialize` over owned
+//! primitives or `String`s. No `tsclientlib`, `cpal`, or backend
+//! types may appear in the public surface (SAD-067, SDD-079).
+//!
+//! Note: this crate cannot use `#![forbid(unsafe_code)]` because the
+//! FRB-generated glue (in `frb_generated`) legitimately uses unsafe
+//! for the FFI boundary. Hand-written code in this crate must
+//! nonetheless avoid `unsafe` and is held to that standard by review.
 
-#![forbid(unsafe_code)]
 #![warn(missing_docs)]
 
-use serde::{Deserialize, Serialize};
+pub mod api;
+mod frb_generated;
+
 use thiserror::Error;
 
 /// Errors raised at the bridge boundary. Production code must keep
-/// `BridgeError` user-safe — no secrets, no protocol details, no
-/// path information beyond what the redaction policy permits.
-#[derive(Debug, Error, Clone, Serialize, Deserialize)]
+/// these user-safe — no secrets, no protocol details, no path
+/// information beyond what the redaction policy permits.
+#[derive(Debug, Error, Clone, serde::Serialize, serde::Deserialize)]
 pub enum BridgeError {
     /// The caller submitted a malformed command DTO.
     #[error("invalid command: {0}")]
     InvalidCommand(String),
-    /// An unknown / unmapped error escaped the subsystem boundary.
-    /// Production callers should never see this; if it appears it is
-    /// a mapping bug in this crate.
+    /// Connection layer failure (typed-mapped from CoreError).
+    #[error("connection: {0}")]
+    Connection(String),
+    /// Operation requires an active connection.
+    #[error("not connected")]
+    NotConnected,
+    /// Already connected; DEC-006 forbids a second concurrent
+    /// connection.
+    #[error("already connected")]
+    AlreadyConnected,
+    /// An unmapped error escaped the subsystem boundary. Production
+    /// callers should never see this; if they do, it is a mapping
+    /// bug here.
     #[error("unmapped: {0}")]
     Unmapped(String),
 }
 
-#[cfg(test)]
-mod tests {
-    #[test]
-    fn it_compiles() {}
+impl From<chanora_core::CoreError> for BridgeError {
+    fn from(e: chanora_core::CoreError) -> Self {
+        match e {
+            chanora_core::CoreError::NotConnected => BridgeError::NotConnected,
+            chanora_core::CoreError::AlreadyConnected => BridgeError::AlreadyConnected,
+            chanora_core::CoreError::Protocol(p) => BridgeError::Connection(format!("{p}")),
+            other => BridgeError::Unmapped(format!("{other}")),
+        }
+    }
 }