fix(ui): one-word games must not highlight phantom cross words; review polish

Board-highlight bug (reported on the contour): formedGeometry walked cross words
unconditionally, so in a single-word (one-word-per-turn) game a staged tile sitting
next to a committed tile lit up a green "cross word" the engine ignores — and which
need not even be a real word (the reported "БО lights up green in a one-word ПОПА
play"). Gate the cross-word walk on the game's multipleWordsPerTurn flag. The score
(8) was already correct — a premium square under the main word.

Also, from review:
- the turn strip reads the staged play's "WORD+WORD = N" while composing a legal move,
  reverting to the turn / result text otherwise;
- the Exchange/Pass dialog shows the bag count ("In the bag: N" / "Bag is empty")
  right-aligned in the title row, via a new optional Modal `titleAside`;
- cosmetics: half the turn strip's bottom padding (the plaques below carry their own
  top pad); a top gap above the landscape rack (it sat flush under the docked history);
  more horizontal padding on tab count badges so a 2-3 digit bag count clears the pill
  ends;
- admin console: the game Summary now shows the single-word / multiple-words rule.

Tests: formed single-word case added; full unit (584) + e2e (chromium + webkit, 113
each) green; backend build + adminconsole templates parse. Docs (FUNCTIONAL +_ru,
UI_DESIGN) updated.

backend/internal/adminconsole/views.go

@@ -348,8 +348,12 @@ type GameDetailView struct {
 	UpdatedAt   string
 	FinishedAt  string
 	// VsAI marks an honest-AI game (shown as a 🤖 flag in the summary).
-	VsAI  bool
-	Seats []SeatRow
+	VsAI bool
+	// MultipleWordsPerTurn is the game's cross-word rule: true = standard Scrabble (every cross-word
+	// is validated and scored), false = the single-word rule (only the main word along the play
+	// direction counts). Shown in the summary so an operator can tell the rule at a glance.
+	MultipleWordsPerTurn bool
+	Seats                []SeatRow
 	// HasRobot is true when any seat is a robot, gating the robot-target caption;
 	// RobotTargetPct is the configured global play-to-win rate, in percent.
 	HasRobot       bool