feat(quick-260630-gbh-01): avatar storage endpoints + enriched /auth/me

- Add avatarPath String? column to User model (migration: add_user_avatar)
- POST /users/me/avatar: 2MB limit, image/png/jpeg/webp allowlist, writes to user-files/avatars/{userId}.{ext}
- GET /users/me/avatar: streams avatar with Cache-Control: no-store
- AuthService.getMe(): returns isLocalUser + hasAvatar without leaking passwordHash/ldapDn
- AuthController GET /auth/me: now returns enriched profile via getMe()

apps/api/src/auth/auth.service.ts

@@ -182,6 +182,40 @@ export class AuthService {
     this.logger.log(`Password reset completed for user ${resetToken.userId}`);
   }
 
+  /**
+   * Return enriched profile for the currently authenticated user.
+   * T-gbh-03: Only public fields + isLocalUser/hasAvatar returned — never
+   *           passwordHash or ldapDn.
+   */
+  async getMe(userId: string) {
+    const user = await this.prisma.user.findUnique({
+      where: { id: userId },
+      select: {
+        id: true,
+        username: true,
+        displayName: true,
+        role: true,
+        tenantId: true,
+        mustChangePassword: true,
+        passwordHash: true,
+        ldapDn: true,
+        avatarPath: true,
+      },
+    });
+
+    if (!user) {
+      return null;
+    }
+
+    const { passwordHash, ldapDn, avatarPath, ...publicFields } = user;
+
+    return {
+      ...publicFields,
+      isLocalUser: !!passwordHash && !ldapDn,
+      hasAvatar: !!avatarPath,
+    };
+  }
+
   /**
    * Change password for the currently logged-in user.
    * Verifies current password before allowing change.