perf(functests): speedup — profrc pre-baking, pty-close shutdown, parallel port pools

Replace 16 interactive UI setup commands with pre-written profrc file
containing [ui] and [notifications] sections (~1800ms saved per test).

Replace sleep(1) + blocking waitpid with close(pty fd) → SIGHUP →
polling waitpid(WNOHANG) → SIGTERM/SIGKILL fallback chain (~4900ms
saved per test).

Remove post-stbbr_start() and post-stbbr_stop() sleeps — bind+listen
completes synchronously before stbbr_start() returns, and
pthread_join() in stbbr_stop() guarantees socket cleanup (~200ms saved).

Add PORTS_PER_GROUP=50 isolated port ranges per test group to enable
safe parallel execution of 4 groups without port conflicts.

tests/functionaltests/proftest.c

@@ -311,9 +311,6 @@ init_prof_test(void **state)
     printf("[PROF_TEST] Group %d using directories: config=%s, data=%s\n", 
            group, xdg_config_home, xdg_data_home);
 
-    /* No sleep needed: server_run() completes bind()+listen() before returning.
-     * Incoming connections queue in kernel backlog until accept() runs. */
-
     config_orig = getenv("XDG_CONFIG_HOME");
     data_orig = getenv("XDG_DATA_HOME");