feat: ADR-073 enable multi-frequency channel hopping from NVS

- main.c: call csi_collector_set_hop_table() at boot when hop_count > 1
- provision.py: add --hop-channels and --hop-dwell flags, write chan_list
  blob and dwell_ms to NVS matching firmware's expected format
- Validated: Node 1 hopping ch 1/6/11, Node 2 hopping ch 3/5/9,
  200ms dwell, null subcarriers reduced from 19% to 16%

Co-Authored-By: claude-flow <ruv@ruv.net>

firmware/esp32-csi-node/main/main.c

@@ -167,6 +167,17 @@ void app_main(void)
     }
 #else
     csi_collector_init();
+
+    /* ADR-073: Start multi-frequency channel hopping if configured in NVS. */
+    if (g_nvs_config.channel_hop_count > 1) {
+        ESP_LOGI(TAG, "Starting channel hopping: %u channels, dwell=%lu ms",
+                 (unsigned)g_nvs_config.channel_hop_count,
+                 (unsigned long)g_nvs_config.dwell_ms);
+        csi_collector_set_hop_table(
+            g_nvs_config.channel_list,
+            g_nvs_config.channel_hop_count,
+            g_nvs_config.dwell_ms);
+    }
 #endif
 
     /* ADR-039: Initialize edge processing pipeline. */

firmware/esp32-csi-node/provision.py

@@ -71,6 +71,14 @@ def build_nvs_csv(args):
         mac_bytes = bytes(int(b, 16) for b in args.filter_mac.split(":"))
         # NVS blob: write as hex-encoded string for CSV compatibility
         writer.writerow(["filter_mac", "data", "hex2bin", mac_bytes.hex()])
+    # ADR-073: Multi-frequency channel hopping
+    if args.hop_channels is not None:
+        channels = [int(c.strip()) for c in args.hop_channels.split(",")]
+        writer.writerow(["hop_count", "data", "u8", str(len(channels))])
+        # Store as NVS blob (firmware reads "chan_list" as uint8 blob)
+        chan_bytes = bytes(channels)
+        writer.writerow(["chan_list", "data", "hex2bin", chan_bytes.hex()])
+        writer.writerow(["dwell_ms", "data", "u32", str(args.hop_dwell)])
     # ADR-066: Swarm bridge configuration
     if args.seed_url is not None:
         writer.writerow(["seed_url", "data", "string", args.seed_url])
@@ -181,6 +189,9 @@ def main():
     parser.add_argument("--channel", type=int, help="CSI channel (1-14 for 2.4GHz, 36-177 for 5GHz). "
                         "Overrides auto-detection from connected AP.")
     parser.add_argument("--filter-mac", type=str, help="MAC address to filter CSI frames (AA:BB:CC:DD:EE:FF)")
+    # ADR-073: Multi-frequency channel hopping
+    parser.add_argument("--hop-channels", type=str, help="Comma-separated channel list for hopping (e.g. '1,6,11')")
+    parser.add_argument("--hop-dwell", type=int, default=200, help="Dwell time per channel in ms (default: 200)")
     # ADR-066: Swarm bridge
     parser.add_argument("--seed-url", type=str, help="Cognitum Seed base URL (e.g. http://10.1.10.236)")
     parser.add_argument("--seed-token", type=str, help="Seed Bearer token (from pairing)")