Condense obstacle cards into an overlapping column (v2)

Replace the big-original-card + row-of-minis layout with a single vertical
column: the original sits at the back (accent ring), each play stacks in front
with a heavy negative margin so only its rank+suit peeks out, and the latest
card is fully visible at the bottom. Played cards keep a green/red success ring;
the ChallengePanel's per-play list still credits each player.

Top-aligns the Current Difficulty / Successes boxes so they no longer stretch to
the now-taller card column. Matches the rulebook's column card layout and is far
more compact. Verified in the ChallengePanel, the obstacle list, and on mobile.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/lib/changelog.js

@@ -6,10 +6,17 @@
 //   - Add a CHANGELOG entry only when a commit changes something players can
 //     see. Skip refactors, tests, and tooling. Keep wording player-facing.
 
-export const VERSION = 1;
+export const VERSION = 2;
 
 // Newest first. Each entry: { version, date: 'YYYY-MM-DD', changes: [string, ...] }.
 export const CHANGELOG = [
+    {
+        version: 2,
+        date: '2026-06-15',
+        changes: [
+            'Obstacle cards now stack as a single overlapping column — the latest play sits in full view with earlier cards peeking out behind it, matching the rulebook’s card layout.',
+        ],
+    },
     {
         version: 1,
         date: '2026-06-15',