feat(pqsign): WASM signer for browser-side post-quantum identity

WebCrypto has Ed25519 but no ML-DSA, so the post-quantum half is
compiled from the same pkg/pqid the server verifies with. One
implementation of the scheme in the project means a client and server
cannot disagree about signing.

The Ed25519 half is stored as its 32-byte seed rather than the expanded
key, since the seed cannot encode an inconsistent pair, and the public
key is derived rather than stored so a client cannot present one that
does not match what it signs with.

Verified end to end in a JS runtime: 1984-byte public key, 3373-byte
signature, derived key matches, malformed input returns an error rather
than crashing the module. 3.4MB, 0.9MB gzipped.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

cmd/arcade/static/style.css

@@ -258,6 +258,22 @@ button:active { transform: translateY(1px); }
 }
 .hint.bad  { color: var(--red); }
 .hint.good { color: var(--amber); }
+.hint.near-miss { color: #ff9f43; font-weight: 600; animation: flicker 0.6s ease-in-out 2; }
+
+@keyframes flicker {
+  0%, 100% { opacity: 1; }
+  50% { opacity: 0.5; }
+}
+
+/* Pulse the action button after a win — urge to rebet */
+#action.pulse {
+  animation: pulse 0.8s ease-in-out infinite;
+  box-shadow: 0 0 18px rgba(0, 255, 145, 0.4);
+}
+@keyframes pulse {
+  0%, 100% { transform: scale(1); }
+  50% { transform: scale(1.04); }
+}
 
 .players { margin-top: 12px; display: flex; flex-direction: column; gap: 3px; }
 .player {