External Executor Bridge Integration

The OpenClaw bridge should instrument all tool calls:

• Before calling an external tool, increment ainl_tool_calls_total{tool_name} via MetricsCollector.
• After call, log success/failure in metrics.
• If the tool uses an LLM internally, also track costs through the same CostTracker.

Additionally, the bridge may need to respect global throttling: call BudgetPolicy().check_and_enforce(run_id) before expensive operations.