refactor(handler,server): disable SubmitApplication endpoint, replaced by POST /tasks

- Comment out SubmitApplication handler method

- Comment out route registration in server.go (interface + router + placeholder)

- Comment out related handler tests

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

internal/server/server.go

@@ -31,7 +31,7 @@ type ApplicationHandler interface {
 	GetApplication(c *gin.Context)
 	UpdateApplication(c *gin.Context)
 	DeleteApplication(c *gin.Context)
-	SubmitApplication(c *gin.Context)
+	// SubmitApplication(c *gin.Context) // [已禁用] 已被 POST /tasks 取代
 }
 
 type UploadHandler interface {
@@ -93,7 +93,7 @@ func NewRouter(jobH JobHandler, clusterH ClusterHandler, appH ApplicationHandler
 	apps.GET("/:id", appH.GetApplication)
 	apps.PUT("/:id", appH.UpdateApplication)
 	apps.DELETE("/:id", appH.DeleteApplication)
-	apps.POST("/:id/submit", appH.SubmitApplication)
+	// apps.POST("/:id/submit", appH.SubmitApplication) // [已禁用] 已被 POST /tasks 取代
 
 	files := v1.Group("/files")
 
@@ -164,7 +164,7 @@ func registerPlaceholderRoutes(v1 *gin.RouterGroup) {
 	apps.GET("/:id", notImplemented)
 	apps.PUT("/:id", notImplemented)
 	apps.DELETE("/:id", notImplemented)
-	apps.POST("/:id/submit", notImplemented)
+	// apps.POST("/:id/submit", notImplemented) // [已禁用] 已被 POST /tasks 取代
 
 	files := v1.Group("/files")