refactor: replace console.log with structured logger calls

Replace raw `console.log`/`console.error` calls across CLI, API
handlers, and module files with structured logger functions (`step`,
`done`, `warn`, `fail`) from the shared logger library.

This improves log consistency, readability, and makes it easier to
control output formatting and log levels from a single place.

src/shared/lib/init.js

@@ -4,6 +4,7 @@
  */
 
 import { discoverModules, registerExternalModules, startModuleCronJobs, stopModuleCronJobs } from '../../core/modules/index.js';
+import { step, done, warn, fail } from './logger.js';
 
 // Use globalThis to persist initialization flag across module reloads
 const ZEN_INIT_KEY = Symbol.for('__ZEN_INITIALIZED__');
@@ -11,10 +12,10 @@ const ZEN_INIT_KEY = Symbol.for('__ZEN_INITIALIZED__');
 /**
  * Initialize ZEN system
  * Discovers modules dynamically and starts cron jobs
- * 
+ *
  * Recommended: Use instrumentation.js for automatic initialization
  * Alternative: Call this function manually in your root layout
- * 
+ *
  * @example
  * // instrumentation.js (Recommended) — internal modules only
  * export async function register() {
@@ -42,26 +43,26 @@ const ZEN_INIT_KEY = Symbol.for('__ZEN_INITIALIZED__');
  */
 export async function initializeZen(config = {}) {
   const { modules: externalModules = [], skipCron = false, skipDb = true } = config;
-  
+
   // Only run on server-side
   if (typeof window !== 'undefined') {
     return { skipped: true, reason: 'client-side' };
   }
-  
+
   // Prevent multiple initializations using globalThis
   if (globalThis[ZEN_INIT_KEY]) {
-    console.log('⚠ ZEN: Already initialized, skipping...');
+    warn('ZEN: already initialized, skipping');
     return { skipped: true, reason: 'already-initialized' };
   }
-  
+
   globalThis[ZEN_INIT_KEY] = true;
-  console.log('🚀 ZEN: Starting initialization...');
-  
+  step('ZEN starting...');
+
   const result = {
     discovery: null,
     cron: { started: [], errors: [] }
   };
-  
+
   try {
     // Step 1: Discover and register internal modules (from modules.registry.js)
     result.discovery = await discoverModules();
@@ -70,10 +71,10 @@ export async function initializeZen(config = {}) {
     const skippedCount = result.discovery.skipped?.length || 0;
 
     if (enabledCount > 0) {
-      console.log(`✓ ZEN: Discovered ${enabledCount} internal module(s): ${result.discovery.enabled.join(', ')}`);
+      done(`ZEN: ${enabledCount} module(s): ${result.discovery.enabled.join(', ')}`);
     }
     if (skippedCount > 0) {
-      console.log(`⚠ ZEN: Skipped ${skippedCount} disabled module(s): ${result.discovery.skipped.join(', ')}`);
+      warn(`ZEN: skipped ${skippedCount} module(s): ${result.discovery.skipped.join(', ')}`);
     }
 
     // Step 2: Register external modules from zen.config.js (if any)
@@ -81,26 +82,26 @@ export async function initializeZen(config = {}) {
       result.external = await registerExternalModules(externalModules);
 
       if (result.external.registered.length > 0) {
-        console.log(`✓ ZEN: Registered ${result.external.registered.length} external module(s): ${result.external.registered.join(', ')}`);
+        done(`ZEN: ${result.external.registered.length} external module(s): ${result.external.registered.join(', ')}`);
       }
     }
-    
+
     // Step 3: Start cron jobs for all enabled modules (internal + external)
     if (!skipCron) {
       result.cron = await startModuleCronJobs();
-      
+
       if (result.cron.started.length > 0) {
-        console.log(`✓ ZEN: Started ${result.cron.started.length} cron job(s): ${result.cron.started.join(', ')}`);
+        done(`ZEN: ${result.cron.started.length} cron job(s): ${result.cron.started.join(', ')}`);
       }
     }
-    
-    console.log('✓ ZEN: Initialization complete');
-    
+
+    done('ZEN: ready');
+
   } catch (error) {
-    console.error('✗ ZEN: Initialization failed:', error);
+    fail(`ZEN: init failed: ${error.message}`);
     result.error = error.message;
   }
-  
+
   return result;
 }
 
@@ -110,14 +111,13 @@ export async function initializeZen(config = {}) {
  */
 export function resetZenInitialization() {
   globalThis[ZEN_INIT_KEY] = false;
-  
+
   // Stop all cron jobs using the module system
   try {
     stopModuleCronJobs();
   } catch (e) {
     // Cron system not available
   }
-  
-  console.log('⚠ ZEN: Initialization flag reset');
-}
 
+  warn('ZEN: initialization reset');
+}