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/new-hook.ts

@@ -2,7 +2,6 @@ import path from 'path';
 import { stdin } from 'process';
 import { createHookResponse } from './hook-response.js';
 import { ensureWorkerRunning, getWorkerPort } from '../shared/worker-utils.js';
-import { happy_path_error__with_fallback } from '../utils/silent-debug.js';
 import { handleWorkerError } from '../shared/hook-error-handler.js';
 import { handleFetchError } from './shared/error-handler.js';
 
@@ -27,12 +26,6 @@ async function newHook(input?: UserPromptSubmitInput): Promise<void> {
   const { session_id, cwd, prompt } = input;
   const project = path.basename(cwd);
 
-  happy_path_error__with_fallback('[new-hook] Input received', {
-    session_id,
-    project,
-    prompt_length: prompt?.length
-  });
-
   const port = getWorkerPort();
 
   // Initialize session via HTTP - handles DB operations and privacy checks