feat: G15Office job, widget settings and submissions admin, embed.js and the settings importer

- SyncG15Office files each submission as a G15Office task with its screenshot through a fetchguard client limited to the configured host; a River job with 3 attempts, PHP's messages on failure, nothing sent when unconfigured
- the replay of PHP's recorded G15Office exchange (classes/testdata) asserts the task JSON, headers and the screenshot part
- settings screen (cabana field types only), read-only submissions list, manage_settings permission and navigation
- embed.js served byte for byte at /plugins/golem15/feedback/assets/js/embed.js
- feedback:import-settings copies the WinterCMS settings row once

controllers/submissions_admin_controller.go

@@ -0,0 +1,36 @@
+package controllers
+
+import (
+	"git.golem15.com/golem15/sm-feedback-plugin/models"
+	"git.golem15.com/golem15/summercms/modules/pact"
+)
+
+// SubmissionsAdminController is the read-only list of the widget's
+// submissions (golem15.feedback.submissions): no form, no create, no
+// delete. The WinterCMS plugin had no such screen; operators read reports
+// in G15Office, and this list shows what was received and whether it was
+// filed (status, task id).
+type SubmissionsAdminController struct{}
+
+var (
+	_ pact.AdminController   = SubmissionsAdminController{}
+	_ pact.AdminPermissioned = SubmissionsAdminController{}
+	_ pact.AdminRecordSource = SubmissionsAdminController{}
+)
+
+// ID is golem15.feedback.submissions.
+func (SubmissionsAdminController) ID() string { return "golem15.feedback.submissions" }
+
+// ModelName is the model's WinterCMS class name.
+func (SubmissionsAdminController) ModelName() string { return models.Submission{}.MorphName() }
+
+// ConfigDir holds config_list.yaml.
+func (SubmissionsAdminController) ConfigDir() string { return "controllers/submissions" }
+
+// RequiredPermissions is golem15.feedback.manage_settings.
+func (SubmissionsAdminController) RequiredPermissions() []string {
+	return []string{PermissionManageSettings}
+}
+
+// NewRecord returns an empty submission.
+func (SubmissionsAdminController) NewRecord() any { return &models.Submission{} }