feat: UOOC/Zhihuishu dual-platform brushing platform

- ASP.NET Core 9 Web API backend with JWT auth, EF Core MySQL
- Vue 3 + Vite + Pinia + Ant Design Vue frontend
- Multi-platform connection management (UOOC & Zhihuishu)
- Video brushing with AES-CBC encryption for Zhihuishu
- Multi-task queue with cross-platform parallel execution
- Task persistence via MySQL database
- Progress tracking with inline catalog enrichment
- Mobile-responsive UI

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

backend/src/UoocProgress.Api/Controllers/AdminBrushController.cs

@@ -0,0 +1,31 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using UoocProgress.Api.Services;
+
+namespace UoocProgress.Api.Controllers;
+
+[ApiController]
+[Authorize(Policy = "AdminOnly")]
+[Route("api/admin/brush")]
+public sealed class AdminBrushController(VideoBrushService brushService) : ControllerBase
+{
+    [HttpGet("tasks")]
+    public ActionResult<IReadOnlyList<AdminBrushTaskDto>> GetTasks()
+        => Ok(brushService.GetAllTasks());
+
+    [HttpPost("stop/{userId:long}")]
+    public IActionResult Stop(long userId) { brushService.AdminStop(userId); return NoContent(); }
+
+    [HttpPost("stop-all")]
+    public IActionResult StopAll() { brushService.StopAll(); return NoContent(); }
+
+    [HttpGet("config")]
+    public ActionResult<BrushSystemConfig> GetConfig() => Ok(brushService.Config);
+
+    [HttpPut("config")]
+    public ActionResult<BrushSystemConfig> UpdateConfig([FromBody] BrushSystemConfig config)
+    {
+        brushService.Config.PauseNewTasks = config.PauseNewTasks;
+        return Ok(brushService.Config);
+    }
+}