Fix circular dependency crash in worker service

**Problem:**
Worker service crashed on startup with:
  TypeError: Cannot read properties of undefined (reading 'get')
  at new Wd (.../worker-service.cjs:52:131469)

**Root Cause:**
Circular dependency between SettingsDefaultsManager and logger:
  1. SettingsDefaultsManager imports logger
  2. logger imports SettingsDefaultsManager
  3. logger constructor calls SettingsDefaultsManager.get() at init time
  4. When CommonJS resolves the cycle, SettingsDefaultsManager is undefined

**Solution:**
Break the circular dependency by making logger lazy-load its configuration:
  - Change logger.level from initialized in constructor to lazy-loaded
  - Add getLevel() method that loads on first access
  - Update all level checks to use getLevel()

This allows SettingsDefaultsManager to import logger without triggering
the circular dependency, since logger no longer accesses SettingsDefaultsManager
during module initialization.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/services/worker/http/routes/SessionRoutes.ts

@@ -291,6 +291,7 @@ export class SessionRoutes extends BaseRouteHandler {
         ? stripMemoryTagsFromJson(JSON.stringify(tool_input))
         : '{}';
     } catch (error) {
+      logger.debug('SESSION', 'Failed to serialize tool_input', { sessionDbId }, error);
       cleanedToolInput = '{"error": "Failed to serialize tool_input"}';
     }
 
@@ -299,6 +300,7 @@ export class SessionRoutes extends BaseRouteHandler {
         ? stripMemoryTagsFromJson(JSON.stringify(tool_response))
         : '{}';
     } catch (error) {
+      logger.debug('SESSION', 'Failed to serialize tool_result', { sessionDbId }, error);
       cleanedToolResponse = '{"error": "Failed to serialize tool_response"}';
     }