refactor: remove JobTemplate production code

Remove all JobTemplate model, store, handler, migrations, and wiring. Replaced by Application Definition system.

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

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

internal/app/app.go

@@ -21,7 +21,6 @@ import (
 	"gorm.io/gorm"
 )
 
-// App encapsulates the entire application lifecycle.
 type App struct {
 	cfg    *config.Config
 	logger *zap.Logger
@@ -142,13 +141,14 @@ func initSlurmClient(cfg *config.Config) (*slurm.Client, error) {
 func initHTTPServer(cfg *config.Config, db *gorm.DB, slurmClient *slurm.Client, logger *zap.Logger) *http.Server {
 	jobSvc := service.NewJobService(slurmClient, logger)
 	clusterSvc := service.NewClusterService(slurmClient, logger)
-	templateStore := store.NewTemplateStore(db)
-
 	jobH := handler.NewJobHandler(jobSvc, logger)
 	clusterH := handler.NewClusterHandler(clusterSvc, logger)
-	templateH := handler.NewTemplateHandler(templateStore, logger)
 
-	router := server.NewRouter(jobH, clusterH, templateH, logger)
+	appStore := store.NewApplicationStore(db)
+	appSvc := service.NewApplicationService(appStore, jobSvc, cfg.WorkDirBase, logger)
+	appH := handler.NewApplicationHandler(appSvc, logger)
+
+	router := server.NewRouter(jobH, clusterH, appH, logger)
 
 	addr := ":" + cfg.ServerPort