feat(mod): add MuMod config and channel endpoints

Author: clansty

MaiChartManager/Controllers/Mod/MuModController.cs

@@ -0,0 +1,53 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace MaiChartManager.Controllers.Mod;
+
+public record MuModConfigDto(string Channel, string CachePath);
+public record SetChannelDto(string Channel);
+public record EnsureCacheResultDto(bool Success, string? Version, string? Error);
+
+[ApiController]
+[Route("MaiChartManagerServlet/[action]Api")]
+public class MuModController(MuModService muModService) : ControllerBase
+{
+    [HttpGet]
+    public MuModConfigDto GetMuModConfig()
+    {
+        var config = muModService.ReadConfig();
+        return new MuModConfigDto(config.Channel, config.CachePath);
+    }
+
+    [HttpPut]
+    public async Task<EnsureCacheResultDto> SetMuModChannelAndEnsureCache([FromBody] SetChannelDto req)
+    {
+        if (req.Channel != "slow" && req.Channel != "fast")
+        {
+            throw new ArgumentException("Channel must be 'slow' or 'fast'", nameof(req));
+        }
+
+        try
+        {
+            muModService.WriteChannel(req.Channel);
+            var result = await muModService.EnsureCache(CancellationToken.None);
+            return new EnsureCacheResultDto(result.Success, result.Version, result.Error);
+        }
+        catch (Exception e)
+        {
+            return new EnsureCacheResultDto(false, null, e.Message);
+        }
+    }
+
+    [HttpPost]
+    public async Task<EnsureCacheResultDto> EnsureMuModCache()
+    {
+        try
+        {
+            var result = await muModService.EnsureCache(CancellationToken.None);
+            return new EnsureCacheResultDto(result.Success, result.Version, result.Error);
+        }
+        catch (Exception e)
+        {
+            return new EnsureCacheResultDto(false, null, e.Message);
+        }
+    }
+}