Add web terminal for remote tablet/phone access to project terminals

Adds an axum HTTP+WebSocket server that runs alongside the Tauri app,
serving a standalone xterm.js-based terminal UI accessible from any
browser on the local network. Shares the existing ExecSessionManager
via Arc-wrapped stores, with token-based authentication and automatic
session cleanup on disconnect.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/src-tauri/src/web_terminal/server.rs

@@ -0,0 +1,155 @@
+use std::sync::Arc;
+
+use axum::extract::{Query, State as AxumState, WebSocketUpgrade};
+use axum::response::{Html, IntoResponse};
+use axum::routing::get;
+use axum::Router;
+use serde::{Deserialize, Serialize};
+use tokio::sync::watch;
+use tower_http::cors::CorsLayer;
+
+use crate::docker::exec::ExecSessionManager;
+use crate::storage::projects_store::ProjectsStore;
+use crate::storage::settings_store::SettingsStore;
+
+use super::ws_handler;
+
+/// Shared state passed to all axum handlers.
+pub struct WebTerminalState {
+    pub exec_manager: Arc<ExecSessionManager>,
+    pub projects_store: Arc<ProjectsStore>,
+    pub settings_store: Arc<SettingsStore>,
+    pub access_token: String,
+}
+
+/// Manages the lifecycle of the axum HTTP+WS server.
+pub struct WebTerminalServer {
+    shutdown_tx: watch::Sender<()>,
+    port: u16,
+}
+
+#[derive(Deserialize)]
+pub struct TokenQuery {
+    pub token: Option<String>,
+}
+
+#[derive(Serialize)]
+struct ProjectInfo {
+    id: String,
+    name: String,
+    status: String,
+}
+
+impl WebTerminalServer {
+    /// Start the web terminal server on the given port.
+    pub async fn start(
+        port: u16,
+        access_token: String,
+        exec_manager: Arc<ExecSessionManager>,
+        projects_store: Arc<ProjectsStore>,
+        settings_store: Arc<SettingsStore>,
+    ) -> Result<Self, String> {
+        let (shutdown_tx, shutdown_rx) = watch::channel(());
+
+        let shared_state = Arc::new(WebTerminalState {
+            exec_manager,
+            projects_store,
+            settings_store,
+            access_token,
+        });
+
+        let app = Router::new()
+            .route("/", get(serve_html))
+            .route("/ws", get(ws_upgrade))
+            .route("/api/projects", get(list_projects))
+            .layer(CorsLayer::permissive())
+            .with_state(shared_state);
+
+        let addr = format!("0.0.0.0:{}", port);
+        let listener = tokio::net::TcpListener::bind(&addr)
+            .await
+            .map_err(|e| format!("Failed to bind web terminal to {}: {}", addr, e))?;
+
+        log::info!("Web terminal server listening on {}", addr);
+
+        let mut shutdown_rx_clone = shutdown_rx.clone();
+        tokio::spawn(async move {
+            axum::serve(listener, app)
+                .with_graceful_shutdown(async move {
+                    let _ = shutdown_rx_clone.changed().await;
+                })
+                .await
+                .unwrap_or_else(|e| {
+                    log::error!("Web terminal server error: {}", e);
+                });
+            log::info!("Web terminal server shut down");
+        });
+
+        Ok(Self { shutdown_tx, port })
+    }
+
+    /// Stop the server gracefully.
+    pub fn stop(&self) {
+        log::info!("Stopping web terminal server on port {}", self.port);
+        let _ = self.shutdown_tx.send(());
+    }
+
+    pub fn port(&self) -> u16 {
+        self.port
+    }
+}
+
+/// Serve the embedded HTML page.
+async fn serve_html() -> Html<&'static str> {
+    Html(include_str!("terminal.html"))
+}
+
+/// Validate token from query params.
+fn validate_token(state: &WebTerminalState, token: &Option<String>) -> bool {
+    match token {
+        Some(t) => t == &state.access_token,
+        None => false,
+    }
+}
+
+/// WebSocket upgrade handler.
+async fn ws_upgrade(
+    ws: WebSocketUpgrade,
+    AxumState(state): AxumState<Arc<WebTerminalState>>,
+    Query(query): Query<TokenQuery>,
+) -> impl IntoResponse {
+    if !validate_token(&state, &query.token) {
+        return (axum::http::StatusCode::UNAUTHORIZED, "Invalid token").into_response();
+    }
+    ws.on_upgrade(move |socket| ws_handler::handle_connection(socket, state))
+        .into_response()
+}
+
+/// List running projects (REST endpoint).
+async fn list_projects(
+    AxumState(state): AxumState<Arc<WebTerminalState>>,
+    Query(query): Query<TokenQuery>,
+) -> impl IntoResponse {
+    if !validate_token(&state, &query.token) {
+        return (
+            axum::http::StatusCode::UNAUTHORIZED,
+            axum::Json(serde_json::json!({"error": "Invalid token"})),
+        )
+            .into_response();
+    }
+
+    let projects = state.projects_store.list();
+    let infos: Vec<ProjectInfo> = projects
+        .into_iter()
+        .map(|p| ProjectInfo {
+            id: p.id,
+            name: p.name,
+            status: serde_json::to_value(&p.status)
+                .ok()
+                .and_then(|v| v.as_str().map(|s| s.to_string()))
+                .unwrap_or_else(|| "unknown".to_string()),
+        })
+        .collect();
+
+    axum::Json(infos).into_response()
+}