fix: generate checksums on API asset upload, not just CreateRelease

The API endpoint POST /releases/{id}/assets bypasses CreateRelease
and UpdateRelease, so checksums were not generated for API uploads.
Added GenerateReleaseChecksums call after successful asset upload.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

routers/api/v1/repo/release_attachment.go

@@ -18,6 +18,7 @@ import (
 	"git.mokoconsulting.tech/MokoConsulting/MokoGitea/services/context"
 	"git.mokoconsulting.tech/MokoConsulting/MokoGitea/services/context/upload"
 	"git.mokoconsulting.tech/MokoConsulting/MokoGitea/services/convert"
+	release_service "git.mokoconsulting.tech/MokoConsulting/MokoGitea/services/release"
 )
 
 func checkReleaseMatchRepo(ctx *context.APIContext, releaseID int64) bool {
@@ -263,6 +264,14 @@ func CreateReleaseAttachment(ctx *context.APIContext) {
 		return
 	}
 
+	// Regenerate checksums after new attachment
+	rel, relErr := repo_model.GetReleaseByID(ctx, releaseID)
+	if relErr == nil {
+		if checksumErr := release_service.GenerateReleaseChecksums(ctx, rel); checksumErr != nil {
+			log.Error("GenerateReleaseChecksums after upload: %v", checksumErr)
+		}
+	}
+
 	ctx.JSON(http.StatusCreated, convert.ToAPIAttachment(ctx.Repo.Repository, attach))
 }