feat(game): official first-move tile draw + admin step-by-step replay

Decide who moves first by the official rule: each seated player draws one
tile, the one closest to "A" leads (a blank beats every letter), ties
re-drawing until a single leader remains. Each draw uses honest per-draw
crypto/rand entropy (not the deterministic bag seed), so the recorded draw —
not a seed — is the only account of the outcome. The leader takes seat 0, so
the engine and journal replay are unchanged.

The draw is recorded with the game (game_setup_draws, migration 00013) for
future tournaments, designed as a discrete "player N draws a tile" step.
Friend/AI games draw at creation. Auto-match draws when the game opens,
against a synthetic uuid.Nil opponent whose draw rows (NULL account_id) are
back-filled to the real opponent on join — so the opener's seat is fixed up
front and the existing open-game pre-move is preserved with no reseating.

Admin /_gm/games/:id gains the recorded draw list and a simple step-by-step
board replay (game.ReplayTimeline + a vanilla-JS stepper): a board with
A-O/1-15 headers and highlighted premium squares, placed letters with their
tile value as a subscript, rack panels around the board (seat 0 top, 1
bottom, 2 left, 3 right) with the current player highlighted, and a per-move
log with the tiles drawn and the bag remainder.

Docs: ARCHITECTURE §6/§9, FUNCTIONAL (+_ru), PRERELEASE (FM row), design spec.

backend/internal/adminconsole/views.go

@@ -268,6 +268,27 @@ type GameDetailView struct {
 	// RobotTargetPct is the configured global play-to-win rate, in percent.
 	HasRobot       bool
 	RobotTargetPct int
+	// ReplayJSON is the game-replay payload (board, seats, per-step racks/scores/bag) the
+	// game_detail page feeds to its vanilla-JS stepper; HasReplay gates the replay section.
+	ReplayJSON template.JS
+	HasReplay  bool
+	// SetupDraws is the first-move draw — one row per tile drawn (docs/ARCHITECTURE.md §6) —
+	// and FirstMover is the resolved name of the seat-0 player the draw elected.
+	SetupDraws []SetupDrawRow
+	FirstMover string
+}
+
+// SetupDrawRow is one tile drawn in the first-move seeding (docs/ARCHITECTURE.md §6): the
+// round, the player (Name/AccountID, or "(opponent)" with an empty AccountID for an
+// auto-match synthetic draw not yet back-filled), the drawn letter (upper-cased; "?" for a
+// blank) and its draw rank.
+type SetupDrawRow struct {
+	Round     int
+	Name      string
+	AccountID string
+	Letter    string
+	Blank     bool
+	Rank      int
 }
 
 // SeatRow is one seat of a game. For a robot seat (IsRobot) RobotIntent is the game's