feat: parliament daemon, login gate, peer context sync (0.9.13)

Login claims the chair, writes a session ticket, and starts a background
service for discovery plus revision-based context sync. Password Realm
opens require --login (or CST_REALM_PASSWORD); --service/--service-stop
manage the resident agent.

Co-authored-by: Cursor <cursoragent@cursor.com>

include/cst_parliament.h

@@ -44,6 +44,28 @@ int cst_parliament_new_project(const char *project_id);
 int cst_parliament_context_put(const char *text);
 char *cst_parliament_context_get(void);
 
+/* Local login ticket: opens require a fresh chair session (or password env). */
+int cst_parliament_session_write(const char *instance_id);
+int cst_parliament_session_ok(char *instance_id_out, size_t n);
+void cst_parliament_session_clear(void);
+
+/* Apply a peer sync bundle (higher revision already selected by caller). */
+int cst_parliament_apply_sync(unsigned long revision, const char *parliament_id,
+                              const char *project_id, const char *chair,
+                              const char *context);
+
+/* Background parliament service: discover + peer listen + context sync. */
+int cst_parliament_daemon_pidfile(char *out, size_t n);
+int cst_parliament_daemon_running(void);
+/* Start in background (Unix fork). password unlocks Realm in the child.
+ * Returns 0 and writes pid. If already running, returns 0. */
+int cst_parliament_daemon_start(const char *password, const char *instance_id,
+                                int peer_port, char *err, size_t err_sz);
+int cst_parliament_daemon_stop(void);
+/* Foreground service loop (used by --service and the forked child). */
+int cst_parliament_daemon_run(const char *password, const char *instance_id,
+                              int peer_port, char *err, size_t err_sz);
+
 #ifdef __cplusplus
 }
 #endif