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");
+      });
+    }
   }
 
   /**

packages/core/src/mission-store.ts

@@ -103,8 +103,15 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
   ) {
     super();
     this.setMaxListeners(100);
+    // Initialize sequence counter from existing events to ensure uniqueness across restarts
+    const lastEvent = this.db.prepare(`
+      SELECT seq FROM mission_events ORDER BY seq DESC LIMIT 1
+    `).get() as { seq?: number } | undefined;
+    this._eventSeq = lastEvent?.seq ?? 0;
   }
 
+  private _eventSeq = 0;
+
   // ── Row-to-Object Converters ───────────────────────────────────────
 
   /**
@@ -189,6 +196,7 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
       description: row.description,
       metadata: fromJson<Record<string, unknown>>(row.metadata) ?? null,
       timestamp: row.timestamp,
+      seq: row.seq ?? 0,
     };
   }
 
@@ -469,7 +477,7 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
       SELECT missionId, timestamp, description
       FROM mission_events
       WHERE eventType = 'error'
-      ORDER BY timestamp DESC, id DESC
+      ORDER BY seq DESC, id DESC
     `).all() as Array<{ missionId: string; timestamp: string; description: string }>;
     // Only keep the first (latest) error per missionId
     const lastErrorByMission = new Map<string, { timestamp: string; description: string }>();
@@ -603,11 +611,12 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
       description,
       metadata: metadata ?? null,
       timestamp: new Date().toISOString(),
+      seq: ++this._eventSeq,
     };
 
     this.db.prepare(`
-      INSERT INTO mission_events (id, missionId, eventType, description, metadata, timestamp)
-      VALUES (?, ?, ?, ?, ?, ?)
+      INSERT INTO mission_events (id, missionId, eventType, description, metadata, timestamp, seq)
+      VALUES (?, ?, ?, ?, ?, ?, ?)
     `).run(
       event.id,
       event.missionId,
@@ -615,6 +624,7 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
       event.description,
       toJsonNullable(event.metadata),
       event.timestamp,
+      event.seq,
     );
 
     this.db.bumpLastModified();
@@ -726,7 +736,7 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
       SELECT timestamp, description
       FROM mission_events
       WHERE missionId = ? AND eventType = 'error'
-      ORDER BY timestamp DESC, id DESC
+      ORDER BY seq DESC, id DESC
       LIMIT 1
     `).get(missionId) as { timestamp: string; description: string } | undefined;
 

packages/core/src/mission-types.ts

@@ -73,6 +73,8 @@ export interface MissionEvent {
   description: string;
   metadata: Record<string, unknown> | null;
   timestamp: string;
+  /** Monotonically increasing sequence number for ordering events with identical timestamps */
+  seq: number;
 }
 
 /** Computed mission health snapshot used by observability APIs. */