Step 3.3b: status.ptp for the web UI

- ptp_clock_status() adds status.ptp: state (LISTENING / UNCALIBRATED /
  SLAVE), locked, gm_id, offset_ns, freq_ppb, path_delay_ns +
  path_delay_sd_ns (window of 64, from lock on), steps_removed,
  gm_time/freq_traceable, version, own_class (255 slave / 248 auto,
  master), clock_id, gm_class/accuracy/p1/p2, sync_avg/min/max_ms and
  sync_jitter_us (HW Sync intervals), announce_avg_ms, delay_req/resp
  counters, hw_ts, window. Snapshot under a mutex shared with the PTP task.
- Per-Sync log moved to debug; info level logs state changes plus a
  60 s summary (max |offset|, freq, delay).
- Verified vs ptp4l: LISTENING -> UNCALIBRATED -> SLAVE in ~35 s;
  locked offset within a few hundred ns, delay 10.27 us +-0.20 us,
  Delay_Req/Resp 69/69, Sync avg 1000.097 ms, Announce avg 2000 ms.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

components/aes67_ptp/aes67_ptp.c

@@ -1,6 +1,7 @@
 #include "aes67_ptp.h"
 
 #include "aes67_cfg.h"
+#include "aes67_web.h"
 #include "ptp_clock.h"
 #include "ptp_hw.h"
 
@@ -38,5 +39,9 @@ esp_err_t aes67_ptp_start(esp_eth_handle_t eth)
     if (err != ESP_OK) {
         return err;
     }
-    return ptp_clock_start(netif);
+    err = ptp_clock_start(netif);
+    if (err == ESP_OK) {
+        err = status_register(ptp_clock_status);
+    }
+    return err;
 }