feat(game): race exit warnings in the turn report (#12)

Surface the inactivity-removal countdown the rules promise but the
engine never reported. A race within five turns of being auto-removed
for inactivity gets a personal warning in its own report; every race
within three turns is listed publicly to all participants.

- model: Report.PersonalExitWarning + RacesLeavingSoon ([]RaceExitNotice)
- fbs: RaceExitNotice table + Report.personal_exit_warning /
  races_leaving_soon (regenerated Go + TS bindings)
- transcoder: encode/decode both fields
- engine: ReportExitWarnings fills the recipient's TTL (1..5) and lists
  other non-extinct races with TTL 1..3, excluding the recipient itself
- ui: danger-styled personal banner + "races leaving soon" section
  (hidden when empty), wired into the report view, EN/RU i18n
- docs: rules.txt report-section list, FUNCTIONAL.md 6.4 + RU mirror

Voluntary quit and idle timeout share the TTL countdown and are not
distinguished, per the agreed scope.

pkg/schema/fbs/report/Report.go

@@ -489,8 +489,40 @@ func (rcv *Report) UnidentifiedGroupLength() int {
 	return 0
 }
 
+func (rcv *Report) PersonalExitWarning() uint32 {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(56))
+	if o != 0 {
+		return rcv._tab.GetUint32(o + rcv._tab.Pos)
+	}
+	return 0
+}
+
+func (rcv *Report) MutatePersonalExitWarning(n uint32) bool {
+	return rcv._tab.MutateUint32Slot(56, n)
+}
+
+func (rcv *Report) RacesLeavingSoon(obj *RaceExitNotice, j int) bool {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(58))
+	if o != 0 {
+		x := rcv._tab.Vector(o)
+		x += flatbuffers.UOffsetT(j) * 4
+		x = rcv._tab.Indirect(x)
+		obj.Init(rcv._tab.Bytes, x)
+		return true
+	}
+	return false
+}
+
+func (rcv *Report) RacesLeavingSoonLength() int {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(58))
+	if o != 0 {
+		return rcv._tab.VectorLen(o)
+	}
+	return 0
+}
+
 func ReportStart(builder *flatbuffers.Builder) {
-	builder.StartObject(26)
+	builder.StartObject(28)
 }
 func ReportAddVersion(builder *flatbuffers.Builder, version uint64) {
 	builder.PrependUint64Slot(0, version, 0)
@@ -624,6 +656,15 @@ func ReportAddUnidentifiedGroup(builder *flatbuffers.Builder, unidentifiedGroup
 func ReportStartUnidentifiedGroupVector(builder *flatbuffers.Builder, numElems int) flatbuffers.UOffsetT {
 	return builder.StartVector(4, numElems, 4)
 }
+func ReportAddPersonalExitWarning(builder *flatbuffers.Builder, personalExitWarning uint32) {
+	builder.PrependUint32Slot(26, personalExitWarning, 0)
+}
+func ReportAddRacesLeavingSoon(builder *flatbuffers.Builder, racesLeavingSoon flatbuffers.UOffsetT) {
+	builder.PrependUOffsetTSlot(27, flatbuffers.UOffsetT(racesLeavingSoon), 0)
+}
+func ReportStartRacesLeavingSoonVector(builder *flatbuffers.Builder, numElems int) flatbuffers.UOffsetT {
+	return builder.StartVector(4, numElems, 4)
+}
 func ReportEnd(builder *flatbuffers.Builder) flatbuffers.UOffsetT {
 	return builder.EndObject()
 }