diff --git a/.gitignore b/.gitignore
index ee6eb2d..9ea2e2d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -29,3 +29,6 @@ dist-ssr
 .superpowers/
 *.tsbuildinfo
 GITEA_API.md
+
+# Backups (global safety rule keeps these locally; never commit them)
+.backup/
diff --git a/scripts/smoke.py b/scripts/smoke.py
new file mode 100644
index 0000000..cf99915
--- /dev/null
+++ b/scripts/smoke.py
@@ -0,0 +1,89 @@
+#!/usr/bin/env python3
+"""End-to-end smoke test driving the real app in a browser.
+
+Engine vitest covers move logic; this covers the Svelte reactivity wiring that
+vitest can't see — specifically the turn glow / interactivity advancing player
+to player (the bug where `active` froze on North after move 1).
+
+Boots `vite` itself, drives chromium via Playwright, asserts a full N->S->E->W
+round plays and each player's two boards light up in turn. Self-contained:
+
+    python3 scripts/smoke.py
+
+Needs system chromium + the `playwright` python package. Exits non-zero on failure.
+"""
+import subprocess, sys, time, urllib.request, os, signal
+from playwright.sync_api import sync_playwright
+
+ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+URL = "http://localhost:5177/duplicate/"
+BID = ["NW", "NE", "SW", "SE"]
+# (player, board to act on, from-square, to-square) — one legal opening per player.
+ROUND = [("N", "NW", "e2", "e4"), ("S", "SW", "d2", "d4"),
+         ("E", "NE", "e7", "e5"), ("W", "SW", "d7", "d5")]
+EXPECT_ACTIVE = {"N": {"NW", "NE"}, "S": {"SW", "SE"},
+                 "E": {"NE", "SE"}, "W": {"NW", "SW"}}
+
+
+def wait_server(timeout=30):
+    for _ in range(timeout * 2):
+        try:
+            urllib.request.urlopen(URL, timeout=1); return True
+        except Exception:
+            time.sleep(0.5)
+    return False
+
+
+def active_boards(pg):
+    return {BID[i] for i, bd in enumerate(pg.query_selector_all(".board"))
+            if "active" in (bd.get_attribute("class") or "")}
+
+
+def piece_at(pg, board, sq):
+    bi = BID.index(board)
+    span = pg.locator(".board").nth(bi).locator(f'button[aria-label="{sq}"] span.pc')
+    return span.inner_text() if span.count() else None
+
+
+def click(pg, board, sq):
+    pg.locator(".board").nth(BID.index(board)).locator(f'button[aria-label="{sq}"]').click()
+    pg.wait_for_timeout(80)
+
+
+def main():
+    vite = subprocess.Popen(["pnpm", "dev", "--port", "5177"], cwd=ROOT,
+                            stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL,
+                            preexec_fn=os.setsid)
+    try:
+        assert wait_server(), "vite did not come up"
+        with sync_playwright() as p:
+            b = p.chromium.launch(executable_path="/usr/bin/chromium", args=["--no-sandbox"])
+            pg = b.new_page(viewport={"width": 1400, "height": 1000})
+            pg.goto(URL, wait_until="networkidle"); pg.wait_for_timeout(300)
+
+            for player, board, frm, to in ROUND:
+                got = active_boards(pg)
+                assert got == EXPECT_ACTIVE[player], \
+                    f"{player}'s turn: expected active {EXPECT_ACTIVE[player]}, got {got}"
+                other = next(x for x in EXPECT_ACTIVE[player] if x != board)
+                click(pg, board, frm)
+                click(pg, board, to)
+                # move must apply IDENTICALLY on both of the player's boards
+                for bd in (board, other):
+                    assert piece_at(pg, bd, frm) is None, f"{player} {bd} {frm} not vacated"
+                    assert piece_at(pg, bd, to) is not None, f"{player} {bd} {to} empty after move"
+                print(f"OK  {player}: {frm}{to} applied on {board}+{other}, turn advanced")
+
+            assert active_boards(pg) == EXPECT_ACTIVE["N"], "did not cycle back to North"
+            print("OK  full N->S->E->W round cycled back to North")
+            b.close()
+        print("\nSMOKE PASS")
+    finally:
+        os.killpg(os.getpgid(vite.pid), signal.SIGTERM)
+
+
+if __name__ == "__main__":
+    try:
+        main()
+    except AssertionError as e:
+        print(f"\nSMOKE FAIL: {e}"); sys.exit(1)
diff --git a/src/lib/Compass.svelte b/src/lib/Compass.svelte
index cd4c50c..ae3a44e 100644
--- a/src/lib/Compass.svelte
+++ b/src/lib/Compass.svelte
@@ -15,7 +15,10 @@
   const BOARD_IDS: BoardId[] = ['NW', 'NE', 'SW', 'SE'];
 
   let view = $derived(gameStore.view);
-  let active = $derived(gameStore.activeBoards);
+  // Derive from the reactive `view`, NOT the store's #game getter: #game is
+  // deliberately not a $state proxy, so a $derived reading it never recomputes
+  // and the turn glow/interactivity froze on North after move 1.
+  let active = $derived(PLAYER_BOARDS[view.currentPlayer]);
 
   /** Ghost squares for a given board. */
   function ghostsFor(id: BoardId): Square[] {
diff --git a/src/lib/stores/game.svelte.ts b/src/lib/stores/game.svelte.ts
index f9d6f7c..fb9d9a1 100644
--- a/src/lib/stores/game.svelte.ts
+++ b/src/lib/stores/game.svelte.ts
@@ -3,7 +3,6 @@ import { legalSyncedMoves, selectionHighlight, type SelectionHighlight } from '.
 import { ghosts } from '../../engine/ghosts';
 import { evaluateStatus } from '../../engine/endgame';
 import { serialize, deserialize } from '../../engine/notation';
-import { PLAYER_BOARDS } from '../../engine/boards';
 import type {
   BoardId, Player, Square, SyncMove, HistoryEntry, GhostMarker, GameStatus,
 } from '../../engine/types';
@@ -54,11 +53,6 @@ class GameStore {
     return this.scrubPly !== null;
   }
 
-  /** Which boards belong to the player to move (for the turn glow). */
-  get activeBoards(): [BoardId, BoardId] {
-    return PLAYER_BOARDS[this.#game.currentPlayer];
-  }
-
   /** Grab a piece: must be the current player's turn and a live (non-scrub) view. */
   select(square: Square): void {
     if (this.isScrubbing) return;