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.

docs/FUNCTIONAL.md

@@ -211,8 +211,9 @@ tile that extends
 an existing word (down a column or across a row) is accepted. A play is validated
 against the game's dictionary at submit time and scored; an unlimited preview shows
 **on the board itself** whether the tentative move is legal — the staged tiles turn a light
-green once they form a word, a shade darker on the board tiles the word runs through, or a
-calm pink when they form none — and an **orange badge** on the main word carries the move's
+green once they form a word, a shade darker on the board tiles the word runs through (in a
+one-word-per-turn game only the main word), or a calm pink when they form none — and an
+**orange badge** on the main word carries the move's
 score. The confirm control is offered only once the move is legal. The preview is
 computed **on-device** for an instant response once the game's dictionary has loaded — a
 brief warm-up shows on the first open otherwise — and falls back to the server whenever the