feat(runtime): add local codex daemon pairing

server/pkg/db/queries/runtime.sql

@@ -0,0 +1,41 @@
+-- name: ListAgentRuntimes :many
+SELECT * FROM agent_runtime
+WHERE workspace_id = $1
+ORDER BY created_at ASC;
+
+-- name: GetAgentRuntime :one
+SELECT * FROM agent_runtime
+WHERE id = $1;
+
+-- name: GetAgentRuntimeForWorkspace :one
+SELECT * FROM agent_runtime
+WHERE id = $1 AND workspace_id = $2;
+
+-- name: UpsertAgentRuntime :one
+INSERT INTO agent_runtime (
+    workspace_id,
+    daemon_id,
+    name,
+    runtime_mode,
+    provider,
+    status,
+    device_info,
+    metadata,
+    last_seen_at
+) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, now())
+ON CONFLICT (workspace_id, daemon_id, provider)
+DO UPDATE SET
+    name = EXCLUDED.name,
+    runtime_mode = EXCLUDED.runtime_mode,
+    status = EXCLUDED.status,
+    device_info = EXCLUDED.device_info,
+    metadata = EXCLUDED.metadata,
+    last_seen_at = now(),
+    updated_at = now()
+RETURNING *;
+
+-- name: UpdateAgentRuntimeHeartbeat :one
+UPDATE agent_runtime
+SET status = 'online', last_seen_at = now(), updated_at = now()
+WHERE id = $1
+RETURNING *;