Stage 17: backend defect fixes (nudge code, TG name, robot names/timing, multi-device push, move-duration metric + admin analytics)

- #3 nudge-on-own-turn: distinct result code nudge_own_turn + i18n (was reused 'not_your_turn')
- #2 sanitize connector registration name to the editable format; Player/Игрок-XXXXX fallback
- #5 variant-aware robot name pools (composed full/colloquial first + surname forms; ru gets <=20% latin)
- #4 move-number-aware robot move timing (early 1-5min -> late 10-90min, skew k=4)
- #7 emit move event to the actor too (multi-device sync); opponent_moved stays in-app only
- #1 live game_move_duration{variant,phase} histogram + admin console per-user min/avg/max columns and an inline-SVG move-time-by-move-number chart (offline from the journal)
- ProvisionRobot bypasses editor name validation (system names like 'Peter J.')

backend/internal/lobby/lobby.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/google/uuid"
 
+	"scrabble/backend/internal/engine"
 	"scrabble/backend/internal/game"
 )
 
@@ -25,7 +26,7 @@ type GameCreator interface {
 // auto-match. robot.Service satisfies it; it returns an error when no robot is
 // available so the matchmaker can defer substitution.
 type RobotProvider interface {
-	Pick() (uuid.UUID, error)
+	Pick(variant engine.Variant) (uuid.UUID, error)
 }
 
 // Blocker reports whether two accounts have a block between them (either

backend/internal/lobby/matchmaker.go

@@ -197,12 +197,12 @@ func (m *Matchmaker) Reap(ctx context.Context, now time.Time) {
 	}
 	var subs []sub
 	for _, acc := range due {
-		robotID, err := m.robots.Pick()
+		variant := m.queued[acc]
+		robotID, err := m.robots.Pick(variant)
 		if err != nil {
 			m.log.Warn("robot substitution deferred", zap.Error(err))
 			continue
 		}
-		variant := m.queued[acc]
 		m.removeLocked(acc, variant)
 		seats := []uuid.UUID{acc, robotID}
 		if m.rng.Intn(2) == 0 {

backend/internal/lobby/matchmaker_test.go

@@ -28,13 +28,15 @@ func (f *fakeCreator) Create(_ context.Context, p game.CreateParams) (game.Game,
 }
 
 // fakeRobots is a RobotProvider returning a fixed robot id, or an error to model
-// an empty pool.
+// an empty pool. It records the variant of the last substitution request.
 type fakeRobots struct {
-	id  uuid.UUID
-	err error
+	id          uuid.UUID
+	err         error
+	lastVariant engine.Variant
 }
 
-func (f *fakeRobots) Pick() (uuid.UUID, error) {
+func (f *fakeRobots) Pick(variant engine.Variant) (uuid.UUID, error) {
+	f.lastVariant = variant
 	if f.err != nil {
 		return uuid.Nil, f.err
 	}