feat(storage): refactor storage config and remove module registry

Introduce a dedicated `storage-config.js` for registering public
prefixes and access policies via `configureStorageApi()`, replacing the
previous `getAllStoragePublicPrefixes` / `getAllStorageAccessPolicies`
imports from the module registry.

Remove `getAllApiRoutes()` from the router so module-level routes are no
longer auto-collected; feature routes must now be registered explicitly
via `registerFeatureRoutes()` during `initializeZen()`.

Update `.env.example` to document separate `ZEN_STORAGE_PROVIDER`,
`ZEN_STORAGE_B2_*` variables for Backblaze B2 alongside the existing
Cloudflare R2 variables, making provider selection explicit.

Clean up admin navigation and page components to drop module-injected
nav entries, keeping only core and system sections.

src/shared/lib/init.js

@@ -1,136 +1,49 @@
 /**
  * ZEN Initialization
- * Initialize all ZEN services and modules using dynamic module discovery
- */
-
-import { discoverModules, registerExternalModules, startModuleCronJobs, stopModuleCronJobs } from '../../core/modules/index.js';
-import { configureRouter, registerFeatureRoutes, clearFeatureRoutes, clearRouterConfig } from '../../core/api/index.js';
-import { validateSession } from '../../features/auth/lib/session.js';
-import { routes as authRoutes } from '../../features/auth/api.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__');
-
-/**
- * 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
+ * Wires core feature dependencies into the API router.
+ * This is the composition root — the only place that connects features to core.
  *
  * @example
- * // instrumentation.js (Recommended) — internal modules only
+ * // instrumentation.js
  * export async function register() {
  *   if (process.env.NEXT_RUNTIME === 'nodejs') {
  *     const { initializeZen } = await import('@zen/core');
  *     await initializeZen();
  *   }
  * }
- *
- * @example
- * // instrumentation.js — with external modules from zen.config.js
- * import zenConfig from './zen.config.js';
- * export async function register() {
- *   if (process.env.NEXT_RUNTIME === 'nodejs') {
- *     const { initializeZen } = await import('@zen/core');
- *     await initializeZen(zenConfig);
- *   }
- * }
- *
- * @param {Object} config - Configuration object
- * @param {Array}   config.modules  - External module configs (from zen.config.js)
- * @param {boolean} config.skipCron - Skip cron job initialization
- * @param {boolean} config.skipDb   - Skip database initialization
- * @returns {Promise<Object>} Initialization result
  */
-export async function initializeZen(config = {}) {
-  const { modules: externalModules = [], skipCron = false, skipDb = true } = config;
 
-  // Only run on server-side
+import { configureRouter, registerFeatureRoutes, clearRouterConfig, clearFeatureRoutes } from '../../core/api/index.js';
+import { validateSession } from '../../features/auth/lib/session.js';
+import { routes as authRoutes } from '../../features/auth/api.js';
+import { done, warn } from './logger.js';
+
+const ZEN_INIT_KEY = Symbol.for('__ZEN_INITIALIZED__');
+
+export async function initializeZen() {
   if (typeof window !== 'undefined') {
     return { skipped: true, reason: 'client-side' };
   }
 
-  // Prevent multiple initializations using globalThis
   if (globalThis[ZEN_INIT_KEY]) {
     warn('ZEN: already initialized, skipping');
     return { skipped: true, reason: 'already-initialized' };
   }
 
   globalThis[ZEN_INIT_KEY] = true;
-  step('ZEN starting...');
 
-  const result = {
-    discovery: null,
-    cron: { started: [], errors: [] }
-  };
+  configureRouter({ resolveSession: validateSession });
+  registerFeatureRoutes(authRoutes);
 
-  try {
-    // Step 1: Wire core feature dependencies into the API router.
-    // init.js is the composition root — the only place that wires features
-    // into core, keeping core/api/ free of static feature-level imports.
-    configureRouter({ resolveSession: validateSession });
-    registerFeatureRoutes(authRoutes);
+  done('ZEN: ready');
 
-    // Step 2: Discover and register internal modules (from modules.registry.js)
-    result.discovery = await discoverModules();
-
-    const enabledCount = result.discovery.enabled?.length || 0;
-    const skippedCount = result.discovery.skipped?.length || 0;
-
-    if (enabledCount > 0) {
-      done(`ZEN: ${enabledCount} module(s): ${result.discovery.enabled.join(', ')}`);
-    }
-    if (skippedCount > 0) {
-      warn(`ZEN: skipped ${skippedCount} module(s): ${result.discovery.skipped.join(', ')}`);
-    }
-
-    // Step 3: Register external modules from zen.config.js (if any)
-    if (externalModules.length > 0) {
-      result.external = await registerExternalModules(externalModules);
-
-      if (result.external.registered.length > 0) {
-        done(`ZEN: ${result.external.registered.length} external module(s): ${result.external.registered.join(', ')}`);
-      }
-    }
-
-    // Step 4: Start cron jobs for all enabled modules (internal + external)
-    if (!skipCron) {
-      result.cron = await startModuleCronJobs();
-
-      if (result.cron.started.length > 0) {
-        done(`ZEN: ${result.cron.started.length} cron job(s): ${result.cron.started.join(', ')}`);
-      }
-    }
-
-    done('ZEN: ready');
-
-  } catch (error) {
-    fail(`ZEN: init failed: ${error.message}`);
-    result.error = error.message;
-  }
-
-  return result;
+  return {};
 }
 
-/**
- * Reset initialization flag (useful for testing or manual reinitialization)
- * @returns {void}
- */
 export function resetZenInitialization() {
   globalThis[ZEN_INIT_KEY] = false;
-
-  // Stop all cron jobs using the module system
-  try {
-    stopModuleCronJobs();
-  } catch (e) {
-    // Cron system not available
-  }
-
-  // Clear router config and feature routes so they are re-registered on next initializeZen()
   clearRouterConfig();
   clearFeatureRoutes();
-
   warn('ZEN: initialization reset');
 }