refactor: replace happy_path_error__with_fallback with logger.happyPathError (#313)

- Removed all instances of happy_path_error__with_fallback from various hooks, services, and utilities.
- Introduced logger.happyPathError for consistent logging of unexpected nulls and fallback values.
- Updated the logger utility to include a new happyPathError method with enhanced context and stack trace.
- Deprecated silent-debug utility as all logging functionality has been migrated to the logger.

src/hooks/cleanup-hook.ts

@@ -8,7 +8,6 @@
 
 import { stdin } from 'process';
 import { ensureWorkerRunning, getWorkerPort } from '../shared/worker-utils.js';
-import { happy_path_error__with_fallback } from '../utils/silent-debug.js';
 import { HOOK_TIMEOUTS } from '../shared/hook-constants.js';
 
 export interface SessionEndInput {
@@ -23,11 +22,6 @@ async function cleanupHook(input?: SessionEndInput): Promise<void> {
   // Ensure worker is running before any other logic
   await ensureWorkerRunning();
 
-  happy_path_error__with_fallback('[cleanup-hook] Hook fired', {
-    session_id: input?.session_id,
-    reason: input?.reason
-  });
-
   if (!input) {
     throw new Error('cleanup-hook requires input from Claude Code');
   }
@@ -48,18 +42,12 @@ async function cleanupHook(input?: SessionEndInput): Promise<void> {
       signal: AbortSignal.timeout(HOOK_TIMEOUTS.DEFAULT)
     });
 
-    if (response.ok) {
-      const result = await response.json();
-      happy_path_error__with_fallback('[cleanup-hook] Session cleanup completed', result);
-    } else {
+    if (!response.ok) {
       // Non-fatal - session might not exist
-      happy_path_error__with_fallback('[cleanup-hook] Session not found or already cleaned up');
+      console.error('[cleanup-hook] Session not found or already cleaned up');
     }
   } catch (error: any) {
-    // Worker might not be running - that's okay
-    happy_path_error__with_fallback('[cleanup-hook] Worker not reachable (non-critical)', {
-      error: error.message
-    });
+    // Worker might not be running - that's okay (non-critical)
   }
 
   console.log('{"continue": true, "suppressOutput": true}');