feat: Enable Phase C feature flag for Active Identity migration

- Set DROP_SETTINGS_ACTIVEDID to true since Migration 004 dropped the column
- Update documentation to reflect current migration state
- Fix code formatting for consistency

Migration 004 successfully completed at 2025-08-22T10:30Z, enabling
the legacy activeDid column removal feature flag.

src/config/featureFlags.ts

@@ -17,14 +17,16 @@ export const FLAGS = {
   /**
    * Controls Phase C column removal from settings table
    * Set to true when ready to drop the legacy activeDid column
+   * 
+   * ✅ ENABLED: Migration 004 has dropped the activeDid column (2025-08-22T10:30Z)
    */
-  DROP_SETTINGS_ACTIVEDID: false,
+  DROP_SETTINGS_ACTIVEDID: true,
 
   /**
    * Log warnings when dual-read falls back to legacy settings.activeDid
    * Useful for monitoring migration progress
    */
-  LOG_ACTIVE_ID_FALLBACK: process.env.NODE_ENV === 'development',
+  LOG_ACTIVE_ID_FALLBACK: process.env.NODE_ENV === "development",
 
   /**
    * Enable the new active_identity table and migration
@@ -36,7 +38,9 @@ export const FLAGS = {
 /**
  * Get feature flag value with type safety
  */
-export function getFlag<K extends keyof typeof FLAGS>(key: K): typeof FLAGS[K] {
+export function getFlag<K extends keyof typeof FLAGS>(
+  key: K,
+): (typeof FLAGS)[K] {
   return FLAGS[key];
 }