feat(feedback): capture the app version; show version + local Filed time

Each feedback submission now carries the client app version (__APP_VERSION__),
snapshotted like the interface language: FlatBuffers FeedbackSubmitRequest gains
a version field → gateway transcode → backend, persisted in a new nullable
feedback_messages.app_version column (migration 00003, additive so an image
rollback stays DB-safe). The operator console detail shows the app version and
renders the Filed time in UTC plus the sender's time zone (fmtTimeIn).

Touches: fbs schema + regenerated Go/TS codegen, codec + transport (the client
attaches its build), gateway transcode + backendclient, feedback store/service,
admin view + template, docs (ARCHITECTURE §15, FUNCTIONAL + _ru). Verified:
feedback integration tests (migration + version round-trip), codec round-trip,
check/unit/build green.

backend/internal/server/handlers_admin_console.go

@@ -1198,6 +1198,19 @@ func fmtTime(t time.Time) string {
 	return t.UTC().Format("2006-01-02 15:04")
 }
 
+// fmtTimeIn formats a timestamp in the named IANA zone (falling back to UTC when the zone is
+// empty or unknown), or "" when zero — for showing a time in a user's local zone beside UTC.
+func fmtTimeIn(t time.Time, tz string) string {
+	if t.IsZero() {
+		return ""
+	}
+	loc, err := time.LoadLocation(tz)
+	if err != nil {
+		loc = time.UTC
+	}
+	return t.In(loc).Format("2006-01-02 15:04")
+}
+
 // fmtTimePtr formats an optional timestamp for display, or "" when nil.
 func fmtTimePtr(t *time.Time) string {
 	if t == nil {

backend/internal/server/handlers_admin_feedback.go

@@ -77,6 +77,11 @@ func (s *Server) consoleFeedbackDetail(c *gin.Context) {
 		s.consoleError(c, err)
 		return
 	}
+	// Filed time: always UTC; plus the sender's local zone when it is set and not UTC.
+	localCreated := ""
+	if m.TimeZone != "" && m.TimeZone != "UTC" {
+		localCreated = fmtTimeIn(m.CreatedAt, m.TimeZone)
+	}
 	view := adminconsole.FeedbackDetailView{
 		ID: m.ID.String(), AccountID: m.AccountID.String(), SenderName: m.SenderName,
 		Source: m.Source, Channel: m.Channel, InterfaceLanguage: m.Lang,
@@ -84,6 +89,7 @@ func (s *Server) consoleFeedbackDetail(c *gin.Context) {
 		HasAttachment: m.HasAttachment, AttachmentName: m.AttachmentName, IsImage: feedback.IsImage(m.AttachmentName),
 		Read: m.Read, Archived: m.Archived, Replied: m.Replied, ReplyBody: m.ReplyBody,
 		RepliedAt: fmtTime(m.RepliedAt), CreatedAt: fmtTime(m.CreatedAt),
+		Version: m.Version, CreatedAtLocal: localCreated, TimeZone: m.TimeZone,
 	}
 	if banned, err := s.accounts.HasRole(ctx, m.AccountID, account.RoleFeedbackBanned); err == nil {
 		view.Banned = banned

backend/internal/server/handlers_feedback.go

@@ -16,6 +16,9 @@ type feedbackSubmitRequest struct {
 	Attachment     string `json:"attachment"`
 	AttachmentName string `json:"attachment_name"`
 	Channel        string `json:"channel"`
+	// Version is the client's app version (pkg/version / the SPA build), snapshotted so the
+	// operator sees which build a report came from.
+	Version string `json:"version"`
 }
 
 // feedbackReplyDTO is the operator's reply shown back to the player.
@@ -61,7 +64,7 @@ func (s *Server) handleFeedbackSubmit(c *gin.Context) {
 		}
 		attachment = data
 	}
-	if err := s.feedback.Submit(c.Request.Context(), uid, req.Body, attachment, req.AttachmentName, req.Channel, clientIP(c)); err != nil {
+	if err := s.feedback.Submit(c.Request.Context(), uid, req.Body, attachment, req.AttachmentName, req.Channel, req.Version, clientIP(c)); err != nil {
 		s.abortErr(c, err)
 		return
 	}