feat(feedback): in-app user feedback with admin review and account roles

User-facing Feedback screen (Settings -> Info, registered accounts only): a
message (<=1024 runes) plus one optional attachment, an anti-spam gate (one
unreviewed message at a time), and the operator's inline reply with a
Settings/Info badge. Server-rendered admin console section (/_gm/feedback):
unread/read/archived queue with per-user search, detail with read/reply/
archive/delete/delete-all, safe attachment serving (nosniff, images inline via
<img>, others download-only). Introduces account_roles, the first per-account
role table; feedback_banned blocks only feedback submission, granted/revoked
from /users and the delete-with-block action.

- migration 00004_feedback (feedback_messages + account_roles) + jetgen
- backend internal/feedback (store+service), internal/account/roles.go
- wire: FlatBuffers feedback.submit/get/unread; gateway guest gate (Op.NonGuest,
  is_guest via session resolve) -> guest_forbidden before any backend call
- reply push reuses NotificationEvent with a new admin_reply sub-kind
- UI: /feedback route + screen, attachment picker, badge, channel detection, i18n
- tests: feedback unit (Go+UI), gateway guest-gate, inttest lifecycle, e2e
- docs: PLAN stage 19, ARCHITECTURE s15, FUNCTIONAL(+ru), TESTING, READMEs

backend/internal/server/handlers_admin_console.go

@@ -58,6 +58,8 @@ func (s *Server) registerConsole(router *gin.Engine) {
 	gm.POST("/users/:id/grant-hints", s.consoleGrantHints)
 	gm.POST("/users/:id/block", s.consoleBlockUser)
 	gm.POST("/users/:id/unblock", s.consoleUnblockUser)
+	gm.POST("/users/:id/grant-role", s.consoleGrantRole)
+	gm.POST("/users/:id/revoke-role", s.consoleRevokeRole)
 	gm.GET("/reasons", s.consoleReasons)
 	gm.POST("/reasons", s.consoleCreateReason)
 	gm.POST("/reasons/:id/update", s.consoleUpdateReason)
@@ -68,6 +70,16 @@ func (s *Server) registerConsole(router *gin.Engine) {
 	gm.GET("/complaints", s.consoleComplaints)
 	gm.GET("/complaints/:id", s.consoleComplaintDetail)
 	gm.POST("/complaints/:id/resolve", s.consoleResolveComplaint)
+	if s.feedback != nil {
+		gm.GET("/feedback", s.consoleFeedback)
+		gm.GET("/feedback/:id", s.consoleFeedbackDetail)
+		gm.GET("/feedback/:id/attachment", s.consoleFeedbackAttachment)
+		gm.POST("/feedback/:id/read", s.consoleFeedbackRead)
+		gm.POST("/feedback/:id/reply", s.consoleFeedbackReply)
+		gm.POST("/feedback/:id/archive", s.consoleFeedbackArchive)
+		gm.POST("/feedback/:id/delete", s.consoleFeedbackDelete)
+		gm.POST("/feedback/:id/delete-all", s.consoleFeedbackDeleteAll)
+	}
 	gm.GET("/messages", s.consoleMessages)
 	gm.GET("/messages.csv", s.consoleMessagesCSV)
 	gm.GET("/dictionary", s.consoleDictionary)
@@ -87,6 +99,9 @@ func (s *Server) consoleDashboard(c *gin.Context) {
 	view.Games, _ = s.games.CountGames(ctx, "")
 	view.ActiveGames, _ = s.games.CountGames(ctx, game.StatusActive)
 	view.OpenComplaints, _ = s.games.CountComplaints(ctx, game.StatusComplaintOpen)
+	if s.feedback != nil {
+		view.OpenFeedback, _ = s.feedback.CountUnread(ctx)
+	}
 	if changes, err := s.games.DictionaryChanges(ctx); err == nil {
 		view.PendingChanges = len(changes)
 	}
@@ -316,6 +331,10 @@ func (s *Server) consoleUserDetail(c *gin.Context) {
 			view.Reasons = append(view.Reasons, adminconsole.ReasonOption{ID: r.ID.String(), TextEn: r.TextEn, TextRu: r.TextRu})
 		}
 	}
+	if roles, err := s.accounts.ListRoles(ctx, id); err == nil {
+		view.Roles = roles
+	}
+	view.KnownRoles = account.KnownRoles
 	s.renderConsole(c, "user_detail", "users", acc.DisplayName, view)
 }