refactor(frontend): colocate admin components and split service layer

Move route-specific admin components from components/common/admin into
app/(main)/admin/<feature>/components/. Split AdminService god object into
domain services, fix UploadService to use BaseService, add AdminUploadService,
consolidate DB export into DbManageService, and migrate consumers to the
unified services entry.

frontend/lib/services/admin/log.service.ts

@@ -0,0 +1,53 @@
+import {BaseService} from '@/lib/services/core';
+
+export class AdminLogService extends BaseService {
+  protected static readonly basePath = '/api/v1/admin';
+
+  static async getLogs(cursor: number = 0, limit: number = 200): Promise<{
+    lines: Array<{ index: number; data: string }>;
+    has_more: boolean;
+    next_cursor: number;
+  }> {
+    return this.get('/logs', { cursor, limit });
+  }
+
+  static async getAccessLogs(params: {
+    page: number;
+    page_size: number;
+    username?: string;
+    path?: string;
+    start_time?: string;
+    end_time?: string;
+  }): Promise<{
+    total: number;
+    list: Array<{
+      id: string;
+      user_id: string;
+      username: string;
+      nickname: string;
+      path: string;
+      method: string;
+      ip: string;
+      user_agent: string;
+      headers: string;
+      status: number;
+      latency: number;
+      created_at: string;
+    }>;
+  }> {
+    return this.get('/logs/access', params as Record<string, unknown>);
+  }
+
+  static async getLogsAnalytics(): Promise<{
+    trend: Array<{ date: string; count: number }>;
+    browsers: Array<{ browser: string; count: number }>;
+    top_users: Array<{
+      user_id: string;
+      username: string;
+      nickname: string;
+      count: number;
+    }>;
+  }> {
+    return this.get('/logs/analytics');
+  }
+}