feat(FN-1228): complete Step 1 — Backend API Routes modifications

- Modified POST /api/nodes to make type optional (defaults to 'remote')
- Changed DELETE /api/nodes/:id to return 204 No Content
- Updated GET /api/nodes/:id/metrics to return SystemMetrics from node.systemMetrics
- Added GET /api/mesh/state route for full mesh topology state

packages/core/src/db.ts

@@ -367,6 +367,7 @@ CREATE TABLE IF NOT EXISTS mission_events (
   description TEXT NOT NULL,
   metadata TEXT,
   timestamp TEXT NOT NULL,
+  seq INTEGER NOT NULL DEFAULT 0,
   FOREIGN KEY (missionId) REFERENCES missions(id) ON DELETE CASCADE
 );
 CREATE INDEX IF NOT EXISTS idxMissionEventsMissionId ON mission_events(missionId);
@@ -850,6 +851,17 @@ export class Database {
         this.db.exec(`CREATE INDEX IF NOT EXISTS idxChatMessagesCreatedAt ON chat_messages(createdAt)`);
       });
     }
+
+    if (version < 23) {
+      this.applyMigration(23, () => {
+        this.addColumnIfMissing("milestones", "planningNotes", "TEXT");
+        this.addColumnIfMissing("milestones", "verification", "TEXT");
+        this.addColumnIfMissing("slices", "planningNotes", "TEXT");
+        this.addColumnIfMissing("slices", "verification", "TEXT");
+        this.addColumnIfMissing("slices", "planState", "TEXT NOT NULL DEFAULT 'not_started'");
+        this.addColumnIfMissing("mission_events", "seq", "INTEGER NOT NULL DEFAULT 0");
+      });
+    }
   }
 
   /**