small fix, don't worry about it

app/backend/migrations_goose/20260401163000_baseline.sql

@@ -0,0 +1,7 @@
+-- +goose Up
+-- Baseline migration for goose-managed schema evolution.
+SELECT 1;
+
+-- +goose Down
+-- Baseline down migration intentionally does not mutate schema.
+SELECT 1;

app/backend/migrations_goose/20260401203000_agent_heartbeat_history.sql

@@ -0,0 +1,20 @@
+-- +goose Up
+CREATE TABLE IF NOT EXISTS agent_heartbeats (
+    id VARCHAR(255) PRIMARY KEY,
+    node_agent_id VARCHAR(255) NOT NULL REFERENCES node_agents(id) ON DELETE CASCADE,
+    timestamp TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    status VARCHAR(50) NOT NULL DEFAULT 'unknown',
+    resources JSONB NOT NULL DEFAULT '{}'::jsonb,
+    container_count INTEGER NOT NULL DEFAULT 0,
+    system_load JSONB NOT NULL DEFAULT '{}'::jsonb,
+    uptime BIGINT NOT NULL DEFAULT 0,
+    version VARCHAR(50) NOT NULL DEFAULT '',
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_agent_heartbeats_node_agent_id ON agent_heartbeats(node_agent_id);
+CREATE INDEX IF NOT EXISTS idx_agent_heartbeats_timestamp ON agent_heartbeats(timestamp);
+CREATE INDEX IF NOT EXISTS idx_agent_heartbeats_node_timestamp ON agent_heartbeats(node_agent_id, timestamp DESC);
+
+-- +goose Down
+DROP TABLE IF EXISTS agent_heartbeats;