feat(v2): Add pkt_payload to DMs, update watchdog for single container

- Add pkt_payload column to direct_messages table for stable packet
  hash generation and Analyzer URL linking
- Update insert_direct_message() and DeviceManager to store pkt_payload
- Add test for DM pkt_payload storage (43 tests pass)
- Update watchdog to monitor only mc-webui (meshcore-bridge removed)
- USB reset trigger now fires for mc-webui container failures

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/database.py

@@ -248,14 +248,15 @@ class Database:
             cursor = conn.execute(
                 """INSERT INTO direct_messages
                    (contact_pubkey, direction, content, timestamp, sender_timestamp,
-                    txt_type, snr, path_len, expected_ack, signature, raw_json)
-                   VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)""",
+                    txt_type, snr, path_len, expected_ack, pkt_payload, signature, raw_json)
+                   VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)""",
                 (contact_pubkey, direction, content, timestamp,
                  kwargs.get('sender_timestamp'),
                  kwargs.get('txt_type', 0),
                  kwargs.get('snr'),
                  kwargs.get('path_len'),
                  kwargs.get('expected_ack'),
+                 kwargs.get('pkt_payload'),
                  kwargs.get('signature'),
                  kwargs.get('raw_json'))
             )

app/device_manager.py

@@ -262,6 +262,7 @@ class DeviceManager:
                 sender_timestamp=data.get('sender_timestamp'),
                 snr=data.get('snr'),
                 path_len=data.get('path_len'),
+                pkt_payload=data.get('pkt_payload'),
                 raw_json=json.dumps(data, default=str),
             )
 
@@ -454,6 +455,7 @@ class DeviceManager:
                 content=text,
                 timestamp=ts,
                 expected_ack=event_data.get('expected_ack'),
+                pkt_payload=event_data.get('pkt_payload'),
             )
 
             return {

app/schema.sql

@@ -72,6 +72,7 @@ CREATE TABLE IF NOT EXISTS direct_messages (
     snr                 REAL,
     path_len            INTEGER,
     expected_ack        TEXT,                               -- ACK code for delivery tracking
+    pkt_payload         TEXT,                               -- raw packet payload for hash/analyzer
     signature           TEXT,                               -- dedup signature
     raw_json            TEXT,
     created_at          TEXT NOT NULL DEFAULT (datetime('now')),