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.

game/internal/controller/report.go

@@ -129,6 +129,9 @@ func (c *Cache) ReportRace(ri int, rep *mr.Report, battles []*mr.BattleReport, b
 		rep.Player[i].Relation = "-"
 	}
 
+	// race exit warnings
+	c.ReportExitWarnings(ri, rep)
+
 	// sciences
 	c.ReportLocalScience(ri, rep)
 	c.ReportOtherScience(ri, rep)
@@ -177,6 +180,36 @@ func (c *Cache) ReportRace(ri int, rep *mr.Report, battles []*mr.BattleReport, b
 	c.ReportUnidentifiedGroup(ri, rep)
 }
 
+// ReportExitWarnings fills the inactivity-removal warnings. A race's TTL at
+// report time equals the number of turns remaining before it is auto-removed
+// (it is wiped at the start of turn T+TTL). The recipient gets a personal
+// countdown once it is 5 turns out (rep.PersonalExitWarning); every other
+// non-extinct race within 3 turns of removal is listed publicly
+// (rep.RacesLeavingSoon). Voluntary quit and idle timeout share the TTL
+// countdown and are intentionally not distinguished here.
+func (c *Cache) ReportExitWarnings(ri int, rep *mr.Report) {
+	c.validateRaceIndex(ri)
+
+	rep.PersonalExitWarning = 0
+	if ttl := c.g.Race[ri].TTL; ttl > 0 && ttl <= 5 {
+		rep.PersonalExitWarning = ttl
+	}
+
+	rep.RacesLeavingSoon = rep.RacesLeavingSoon[:0]
+	for i := range c.g.Race {
+		r := &c.g.Race[i]
+		if i == ri || r.Extinct {
+			continue
+		}
+		if r.TTL > 0 && r.TTL <= 3 {
+			rep.RacesLeavingSoon = append(rep.RacesLeavingSoon, mr.RaceExitNotice{
+				Race:      r.Name,
+				TurnsLeft: r.TTL,
+			})
+		}
+	}
+}
+
 func (c *Cache) ReportLocalScience(ri int, rep *mr.Report) {
 	c.validateRaceIndex(ri)
 	r := &c.g.Race[ri]