feat: golem15.feedback plugin with the widget config route

- plugin golem15.feedback (requires golem15.user), its config, lang (en, pl), models and migrations
- typed settings singleton golem15_feedback_settings with the WinterCMS defaults and a widget key generated on first creation
- GET /_feedback/api/v1/{key}/config behind the constant-time key check and the fail-closed Origin allow-list, with the feedback-config and feedback-submit buckets

plugin.go

@@ -0,0 +1,98 @@
+// Package feedback is the golem15.feedback plugin: the embeddable feedback
+// widget of SummerCMS applications. It ports the WinterCMS Golem15.Feedback
+// plugin: the widget's public config and submit routes behind a widget key
+// and an Origin allow-list, the per-user "hide the widget" preference, the
+// settings screen, and the job that files every submission as a G15Office
+// task with its screenshot.
+package feedback
+
+import (
+	"embed"
+	"io/fs"
+	"net/http"
+	"time"
+
+	"git.golem15.com/golem15/sm-feedback-plugin/models"
+	"git.golem15.com/golem15/sm-feedback-plugin/updates"
+	"git.golem15.com/golem15/summercms/modules/backpack"
+	"git.golem15.com/golem15/summercms/modules/pact"
+	"git.golem15.com/golem15/summercms/modules/party"
+	"git.golem15.com/golem15/summercms/modules/surf"
+	"github.com/go-gormigrate/gormigrate/v2"
+)
+
+var (
+	_ party.Plugin        = (*Plugin)(nil)
+	_ pact.HasConfig      = (*Plugin)(nil)
+	_ pact.HasLang        = (*Plugin)(nil)
+	_ pact.HasMigrations  = (*Plugin)(nil)
+	_ pact.HasModels      = (*Plugin)(nil)
+	_ pact.HasRoutes      = (*Plugin)(nil)
+	_ surf.BucketProvider = (*Plugin)(nil)
+)
+
+//go:embed config
+var configFS embed.FS
+
+//go:embed lang
+var langFS embed.FS
+
+// Bucket names of the widget routes (routes.php RateLimiter::for).
+const (
+	BucketConfig = "feedback-config"
+	BucketSubmit = "feedback-submit"
+)
+
+// Plugin is the golem15.feedback plugin.
+type Plugin struct {
+	app *backpack.App
+}
+
+// ID is the plugin ID, also its config and lang namespace.
+func (p *Plugin) ID() string { return "golem15.feedback" }
+
+// Requires is golem15.user: the preference route is JWT-guarded and the
+// preference rides on the user payload.
+func (p *Plugin) Requires() []string { return []string{"golem15.user"} }
+
+// Register keeps the application.
+func (p *Plugin) Register(app *backpack.App) error {
+	p.app = app
+	return nil
+}
+
+// Boot keeps the application.
+func (p *Plugin) Boot(app *backpack.App) error {
+	p.app = app
+	return nil
+}
+
+// ConfigFS ships config/config.yaml, merged under golem15.feedback.*.
+func (p *Plugin) ConfigFS() fs.FS { return configFS }
+
+// LangFS ships the golem15.feedback lang namespace (en, pl).
+func (p *Plugin) LangFS() fs.FS { return langFS }
+
+// Migrations creates the submissions, preferences and settings tables.
+func (p *Plugin) Migrations() []*gormigrate.Migration { return updates.All() }
+
+// Models is Submission, UserPreference and Settings.
+func (p *Plugin) Models() []any { return models.All() }
+
+// Buckets are the widget routes' limits by client IP (behind the trusted
+// proxies): 60 config reads and 10 submissions a minute.
+func (p *Plugin) Buckets() map[string]surf.Bucket {
+	trusted := surf.TrustedProxies(nil)
+	if p.app != nil {
+		trusted = surf.TrustedProxies(p.app.Config)
+	}
+	byIP := func(r *http.Request) string { return surf.ClientIP(r, trusted) }
+	return map[string]surf.Bucket{
+		BucketConfig: {Max: 60, Decay: time.Minute, Key: byIP},
+		BucketSubmit: {Max: 10, Decay: time.Minute, Key: byIP},
+	}
+}
+
+func init() {
+	party.Register(&Plugin{})
+}