fix: respect CLAUDE_MEM_FOLDER_CLAUDEMD_ENABLED setting

The CLAUDE_MEM_FOLDER_CLAUDEMD_ENABLED setting was documented but never
actually checked in code. The folder CLAUDE.md generation ran
unconditionally whenever files were touched.

Changes:
- Add CLAUDE_MEM_FOLDER_CLAUDEMD_ENABLED to SettingsDefaults interface
- Add default value 'false' to DEFAULTS object
- Check setting in ResponseProcessor before calling updateFolderClaudeMdFiles

Fixes the issue identified in issue-600-documentation-audit-features-not-implemented.md:
"The setting CLAUDE_MEM_FOLDER_CLAUDEMD_ENABLED is never read."

src/services/worker/agents/ResponseProcessor.ts

@@ -16,6 +16,8 @@ import { parseObservations, parseSummary, type ParsedObservation, type ParsedSum
 import { updateCursorContextForProject } from '../../integrations/CursorHooksInstaller.js';
 import { updateFolderClaudeMdFiles } from '../../../utils/claude-md-utils.js';
 import { getWorkerPort } from '../../../shared/worker-utils.js';
+import { SettingsDefaultsManager } from '../../../shared/SettingsDefaultsManager.js';
+import { USER_SETTINGS_PATH } from '../../../shared/paths.js';
 import type { ActiveSession } from '../../worker-types.js';
 import type { DatabaseManager } from '../DatabaseManager.js';
 import type { SessionManager } from '../SessionManager.js';
@@ -215,6 +217,11 @@ async function syncAndBroadcastObservations(
 
   // Update folder CLAUDE.md files for touched folders (fire-and-forget)
   // This runs per-observation batch to ensure folders are updated as work happens
+  // Only runs if CLAUDE_MEM_FOLDER_CLAUDEMD_ENABLED is true (default: false)
+  const settings = SettingsDefaultsManager.loadFromFile(USER_SETTINGS_PATH);
+  const folderClaudeMdEnabled = settings.CLAUDE_MEM_FOLDER_CLAUDEMD_ENABLED === 'true';
+
+  if (folderClaudeMdEnabled) {
     const allFilePaths: string[] = [];
     for (const obs of observations) {
       allFilePaths.push(...(obs.files_modified || []));
@@ -232,6 +239,7 @@ async function syncAndBroadcastObservations(
       });
     }
   }
+}
 
 /**
  * Sync summary to Chroma and broadcast to SSE clients

src/shared/SettingsDefaultsManager.ts

@@ -51,6 +51,7 @@ export interface SettingsDefaults {
   // Feature Toggles
   CLAUDE_MEM_CONTEXT_SHOW_LAST_SUMMARY: string;
   CLAUDE_MEM_CONTEXT_SHOW_LAST_MESSAGE: string;
+  CLAUDE_MEM_FOLDER_CLAUDEMD_ENABLED: string;
 }
 
 export class SettingsDefaultsManager {
@@ -96,6 +97,7 @@ export class SettingsDefaultsManager {
     // Feature Toggles
     CLAUDE_MEM_CONTEXT_SHOW_LAST_SUMMARY: 'true',
     CLAUDE_MEM_CONTEXT_SHOW_LAST_MESSAGE: 'false',
+    CLAUDE_MEM_FOLDER_CLAUDEMD_ENABLED: 'false',
   };
 
   /**