✅ test(gateway): add tests for agent-runner-utils and notification-router

- agent-runner-utils: 34 tests covering resolveProviderAndModel,
  resolveToolFilter, createConfiguredAgent, registerAllToolSources,
  createToolCallCollector, safeParseJson, buildDateTimeContext,
  calculateExecutionCost, createTimeoutPromise
- notification-router: 18 tests covering notify with priority
  filtering, quiet hours, channel fallback, broadcast, preferences
- Remove unused createGoalStepSchema and mediaSettingsSchema
- Add SSRF utils to barrel export

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ersinkoc