FX2: wire no-moves reshuffle into the UI swipe-commit path

The rendered swipe-commit path (`plan_and_commit`) bypassed the turn-loop's
no-moves rule: a deadlocked board (no legal swap) stayed stuck on screen because
only `play_turn` checked `!has_legal_swap` and reshuffled, and the UI never calls
`play_turn`.

Factor the post-settle "no legal swaps -> reshuffle" check into a shared
`reshuffle_if_deadlocked` in board.sx and call it from BOTH `play_turn` and
`plan_and_commit`, so the animated UI commit obeys the identical model rule. The
reshuffle runs after the cascade settles (post-`commit_swap`); the AnimMove's
recorded `final` stays the settled pre-reshuffle board, so the cascade animation,
per-round audio, and input gating are unchanged — the reshuffled layout renders on
the next settled frame. No win/lose/turn-accounting change; a reshuffle spends no
move and no score.

Regression test tests/swipe_reshuffle.sx drives the exact UI path (swipe_intent ->
plan_and_commit) on the deadlocked board from tests/level.sx: before = no legal
swaps / in_progress; after = reshuffled (has_legal_swap true, 9 legal swaps, no
immediate match), score/moves/budget unchanged. It FAILS pre-fix (board stays
stuck, has_legal_swap false) and PASSES post-fix.

board_anim.sx

@@ -1,12 +1,13 @@
 // Board motion animation (P6.1) — a PURELY VISUAL timeline the view plays over
 // one player move. The logical model (commit_swap / resolve) stays authoritative:
-// `plan_and_commit` commits the move on the real board exactly as before, then
-// replays the SAME operations on a value-copy of the pre-move board to record the
-// per-step geometry (the swap, each cascade round's matched cells, and each
-// round's per-column fall provenance). Because the copy starts from the identical
-// cells AND RNG state and runs the identical primitives, its recorded `final`
-// board equals the model's settled board gem-for-gem — the animation only ever
-// ends ON the already-decided result, never changes it.
+// `plan_and_commit` commits the move on the real board (and, like the headless
+// turn loop, reshuffles a deadlocked board afterwards), then replays the SAME
+// commit operations on a value-copy of the pre-move board to record the per-step
+// geometry (the swap, each cascade round's matched cells, and each round's
+// per-column fall provenance). Because the copy starts from the identical cells
+// AND RNG state and runs the identical primitives, its recorded `final` board
+// equals the move's settled (pre-reshuffle) board gem-for-gem — the animation only
+// ever ends ON the already-decided cascade result, never changes it.
 //
 // Per-gem idle/select/clear gem animations (P6.3) and score popups / particle FX
 // (P6.2) are NOT here; this step animates board MOTION only: swap slide, matched
@@ -231,9 +232,13 @@ delivering_round :: (mv: *AnimMove, i: s64, kmax: s64) -> s64 {
 }
 
 // Commit the player's swap authoritatively AND record its visual timeline. The
-// real board is mutated by `commit_swap` exactly as the non-animated path did;
-// the recording runs on a separate value-copy taken BEFORE the commit, so it
-// replays the identical cells + RNG stream and its `final` equals `board.cells`.
+// real board is mutated by `commit_swap`, then — exactly like the headless
+// `play_turn` — `reshuffle_if_deadlocked` recovers a stranded board so the rendered
+// game obeys the same no-moves rule. The recording runs on a value-copy taken
+// BEFORE the commit, so it replays the identical cells + RNG stream; the recorded
+// `final` is the SETTLED board the animation ends on. It equals the live board
+// unless a deadlock reshuffle then re-arranged it: that reshuffle is a model step,
+// not part of this move's timeline, so it renders on the next settled frame.
 plan_and_commit :: (board: *Board, a: Cell, b: Cell) -> AnimMove {
     move : AnimMove = ---;
     move.a = a;
@@ -251,6 +256,7 @@ plan_and_commit :: (board: *Board, a: Cell, b: Cell) -> AnimMove {
     move.awarded = mv.cascade.awarded;
     if !mv.legal {
         move.final = board.cells;
+        reshuffle_if_deadlocked(board);
         return move;
     }
 
@@ -296,6 +302,7 @@ plan_and_commit :: (board: *Board, a: Cell, b: Cell) -> AnimMove {
     }
 
     move.final = scratch.cells;
+    reshuffle_if_deadlocked(board);
     move
 }