feat(maestro): serve the configured leader to the web client

The TUI read its leader from `[tui].leader`; the web used `DEFAULT_LEADER`,
a module constant. Rebinding one left the other on `ctrl-a`, so the two
escape hatches hanging off the leader (`leader ctrl-k`, `leader leader`)
moved on one client and not the other.

`GET /api/info` now carries `leader`. The web binds that when it arrives and
rebuilds the leader-owning `CommandSet`, so the `?` overlay and the command
bar render the configured chord; an absent or empty field — an older daemon,
or an unreachable `/api/info` — leaves it on `ctrl-a`.

Chose the existing `[tui].leader` served as-is over a new shared key: one
knob, no precedence rules between two spellings, and no migration for
operators who already set it. The name is a wart — it is the leader for every
client now, not the TUI's — and `docs/COMMAND-BAR.md` and `docs/INSTALL.md`
say so.

crates/maestro-daemon/tests/local_api.rs

@@ -36,6 +36,14 @@ async fn spawn(hostname: &str) -> Harness {
 async fn spawn_with(
     hostname: &str,
     projects: std::sync::Arc<maestro_daemon::projects::ProjectScanner>,
+) -> Harness {
+    spawn_with_leader(hostname, projects, maestro_config::DEFAULT_LEADER).await
+}
+
+async fn spawn_with_leader(
+    hostname: &str,
+    projects: std::sync::Arc<maestro_daemon::projects::ProjectScanner>,
+    leader: &str,
 ) -> Harness {
     let fx = DaemonFixture::new();
     let manager = fx.manager.clone();
@@ -48,6 +56,7 @@ async fn spawn_with(
         "/home/test",
         presets,
         projects,
+        leader,
     ));
     let listener = TcpListener::bind(SocketAddr::from((Ipv4Addr::LOCALHOST, 0)))
         .await
@@ -91,6 +100,38 @@ async fn info_returns_daemon_identity() {
     assert!(resp["version"].is_string());
 }
 
+/// #159: the web client reads its leader off `/api/info` instead of a
+/// hardcoded constant, so the payload has to carry the configured one — not
+/// the default dressed up as one.
+#[tokio::test]
+async fn info_advertises_the_configured_leader() {
+    let h = spawn_with_leader(
+        "naps-laptop",
+        std::sync::Arc::new(maestro_daemon::projects::ProjectScanner::disabled()),
+        "ctrl-b",
+    )
+    .await;
+    let resp: serde_json::Value = reqwest::get(url(h.addr, "/api/info"))
+        .await
+        .unwrap()
+        .json()
+        .await
+        .unwrap();
+    assert_eq!(resp["leader"], "ctrl-b");
+}
+
+#[tokio::test]
+async fn info_reports_the_default_leader_when_unconfigured() {
+    let h = spawn("naps-laptop").await;
+    let resp: serde_json::Value = reqwest::get(url(h.addr, "/api/info"))
+        .await
+        .unwrap()
+        .json()
+        .await
+        .unwrap();
+    assert_eq!(resp["leader"], "ctrl-a");
+}
+
 #[tokio::test]
 async fn info_reports_build_and_instance() {
     // The status indicator needs a release to name and a process to compare