🐛 fix(auth): remove all type-only ConfigService imports

Found and fixed type-only ConfigService imports in 6 service files that were causing "Nest can't resolve dependencies" errors:

- better-auth.service.ts (BetterAuthService)
- ai.service.ts (AiService)
- settings.service.ts
- feedback.service.ts
- credits.service.ts
- jwt-auth.guard.ts
- optional-auth.guard.ts

Type-only imports are erased at compile time, preventing NestJS from injecting the ConfigService class at runtime.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

services/mana-core-auth/src/auth/services/better-auth.service.ts

@@ -20,7 +20,7 @@ import {
 	ForbiddenException,
 	UnauthorizedException,
 } from '@nestjs/common';
-import { type ConfigService } from '@nestjs/config';
+import { ConfigService } from '@nestjs/config';
 import { createBetterAuth, type BetterAuthInstance } from '../better-auth.config';
 import { getDb } from '../../db/connection';
 import { balances, organizationBalances } from '../../db/schema/credits.schema';

services/mana-core-auth/src/common/guards/jwt-auth.guard.ts

@@ -4,7 +4,7 @@ import {
 	type ExecutionContext,
 	UnauthorizedException,
 } from '@nestjs/common';
-import { type ConfigService } from '@nestjs/config';
+import { ConfigService } from '@nestjs/config';
 import * as jwt from 'jsonwebtoken';
 
 @Injectable()

services/mana-core-auth/src/common/guards/optional-auth.guard.ts

@@ -1,5 +1,5 @@
 import { Injectable, type CanActivate, type ExecutionContext } from '@nestjs/common';
-import { type ConfigService } from '@nestjs/config';
+import { ConfigService } from '@nestjs/config';
 import * as jwt from 'jsonwebtoken';
 
 /**

services/mana-core-auth/src/credits/credits.service.ts

@@ -5,7 +5,7 @@ import {
 	ConflictException,
 	ForbiddenException,
 } from '@nestjs/common';
-import { type ConfigService } from '@nestjs/config';
+import { ConfigService } from '@nestjs/config';
 import { eq, and, sql, desc, sum } from 'drizzle-orm';
 import { getDb } from '../db/connection';
 import {

services/mana-core-auth/src/feedback/feedback.service.ts

@@ -1,5 +1,5 @@
 import { Injectable, NotFoundException, ConflictException, Logger } from '@nestjs/common';
-import { type ConfigService } from '@nestjs/config';
+import { ConfigService } from '@nestjs/config';
 import { eq, and, desc, sql, count } from 'drizzle-orm';
 import { getDb } from '../db/connection';
 import { userFeedback, feedbackVotes } from '../db/schema';

services/mana-core-auth/src/settings/settings.service.ts

@@ -1,5 +1,5 @@
 import { Injectable, Logger } from '@nestjs/common';
-import { type ConfigService } from '@nestjs/config';
+import { ConfigService } from '@nestjs/config';
 import { eq } from 'drizzle-orm';
 import { getDb } from '../db/connection';
 import { userSettings } from '../db/schema';