feat: add edit support for env vars, labels, and volumes

- Add POST /apps/{id}/env-vars/{varID}/edit endpoint
- Add POST /apps/{id}/labels/{labelID}/edit endpoint
- Add POST /apps/{id}/volumes/{volumeID}/edit endpoint
- Add inline edit UI with Alpine.js toggle in app_detail template
- Models already support Save() with update when ID != 0

Closes #67

internal/handlers/app.go

@@ -896,6 +896,54 @@ func (h *Handlers) HandleEnvVarDelete() http.HandlerFunc {
 	}
 }
 
+// HandleEnvVarEdit handles editing an existing environment variable.
+func (h *Handlers) HandleEnvVarEdit() http.HandlerFunc {
+	return func(writer http.ResponseWriter, request *http.Request) {
+		appID := chi.URLParam(request, "id")
+		envVarIDStr := chi.URLParam(request, "varID")
+
+		envVarID, parseErr := strconv.ParseInt(envVarIDStr, 10, 64)
+		if parseErr != nil {
+			http.NotFound(writer, request)
+
+			return
+		}
+
+		envVar, findErr := models.FindEnvVar(request.Context(), h.db, envVarID)
+		if findErr != nil || envVar == nil || envVar.AppID != appID {
+			http.NotFound(writer, request)
+
+			return
+		}
+
+		formErr := request.ParseForm()
+		if formErr != nil {
+			http.Error(writer, "Bad Request", http.StatusBadRequest)
+
+			return
+		}
+
+		key := request.FormValue("key")
+		value := request.FormValue("value")
+
+		if key == "" || value == "" {
+			http.Redirect(writer, request, "/apps/"+appID, http.StatusSeeOther)
+
+			return
+		}
+
+		envVar.Key = key
+		envVar.Value = value
+
+		saveErr := envVar.Save(request.Context())
+		if saveErr != nil {
+			h.log.Error("failed to edit env var", "error", saveErr)
+		}
+
+		http.Redirect(writer, request, "/apps/"+appID, http.StatusSeeOther)
+	}
+}
+
 // HandleLabelAdd handles adding a label.
 func (h *Handlers) HandleLabelAdd() http.HandlerFunc {
 	return func(writer http.ResponseWriter, request *http.Request) {
@@ -943,6 +991,54 @@ func (h *Handlers) HandleLabelDelete() http.HandlerFunc {
 	}
 }
 
+// HandleLabelEdit handles editing an existing label.
+func (h *Handlers) HandleLabelEdit() http.HandlerFunc {
+	return func(writer http.ResponseWriter, request *http.Request) {
+		appID := chi.URLParam(request, "id")
+		labelIDStr := chi.URLParam(request, "labelID")
+
+		labelID, parseErr := strconv.ParseInt(labelIDStr, 10, 64)
+		if parseErr != nil {
+			http.NotFound(writer, request)
+
+			return
+		}
+
+		label, findErr := models.FindLabel(request.Context(), h.db, labelID)
+		if findErr != nil || label == nil || label.AppID != appID {
+			http.NotFound(writer, request)
+
+			return
+		}
+
+		formErr := request.ParseForm()
+		if formErr != nil {
+			http.Error(writer, "Bad Request", http.StatusBadRequest)
+
+			return
+		}
+
+		key := request.FormValue("key")
+		value := request.FormValue("value")
+
+		if key == "" || value == "" {
+			http.Redirect(writer, request, "/apps/"+appID, http.StatusSeeOther)
+
+			return
+		}
+
+		label.Key = key
+		label.Value = value
+
+		saveErr := label.Save(request.Context())
+		if saveErr != nil {
+			h.log.Error("failed to edit label", "error", saveErr)
+		}
+
+		http.Redirect(writer, request, "/apps/"+appID, http.StatusSeeOther)
+	}
+}
+
 // HandleVolumeAdd handles adding a volume mount.
 func (h *Handlers) HandleVolumeAdd() http.HandlerFunc {
 	return func(writer http.ResponseWriter, request *http.Request) {
@@ -1021,6 +1117,56 @@ func (h *Handlers) HandleVolumeDelete() http.HandlerFunc {
 	}
 }
 
+// HandleVolumeEdit handles editing an existing volume mount.
+func (h *Handlers) HandleVolumeEdit() http.HandlerFunc {
+	return func(writer http.ResponseWriter, request *http.Request) {
+		appID := chi.URLParam(request, "id")
+		volumeIDStr := chi.URLParam(request, "volumeID")
+
+		volumeID, parseErr := strconv.ParseInt(volumeIDStr, 10, 64)
+		if parseErr != nil {
+			http.NotFound(writer, request)
+
+			return
+		}
+
+		volume, findErr := models.FindVolume(request.Context(), h.db, volumeID)
+		if findErr != nil || volume == nil || volume.AppID != appID {
+			http.NotFound(writer, request)
+
+			return
+		}
+
+		formErr := request.ParseForm()
+		if formErr != nil {
+			http.Error(writer, "Bad Request", http.StatusBadRequest)
+
+			return
+		}
+
+		hostPath := request.FormValue("host_path")
+		containerPath := request.FormValue("container_path")
+		readOnly := request.FormValue("readonly") == "1"
+
+		if hostPath == "" || containerPath == "" {
+			http.Redirect(writer, request, "/apps/"+appID, http.StatusSeeOther)
+
+			return
+		}
+
+		volume.HostPath = hostPath
+		volume.ContainerPath = containerPath
+		volume.ReadOnly = readOnly
+
+		saveErr := volume.Save(request.Context())
+		if saveErr != nil {
+			h.log.Error("failed to edit volume", "error", saveErr)
+		}
+
+		http.Redirect(writer, request, "/apps/"+appID, http.StatusSeeOther)
+	}
+}
+
 // HandlePortAdd handles adding a port mapping.
 func (h *Handlers) HandlePortAdd() http.HandlerFunc {
 	return func(writer http.ResponseWriter, request *http.Request) {