fix: race condition on Connect with Smirk button + sync TS types

The extension's window.smirk injection runs as `<script type=module>`,
which browsers defer until after DOMContentLoaded. The previous
detection (sync check + once at +500ms) could race past that on
heavier Next.js pages, leaving the Connect button stuck greyed-out
even though the extension was installed and unlocked.

Three-layer fix in both `app/page.tsx` and `app/tip/[id]/TipPageClient.tsx`:

  1. Immediate sync check (fast path: extension already there).
  2. Listen for `smirk-ready` CustomEvent (extension v0.2.5+ dispatches it).
  3. Polling fallback at 100ms intervals up to 3s, for older
     extensions or any future browser quirk. Cheap; stops as soon as
     window.smirk appears.

`hasExtension` stays `null` (initial) until either we resolve `true`
or hit the 3s timeout and resolve `false` — so the install prompt
doesn't flash on first paint while polling is still in flight.

Also updated `types/smirk.d.ts` to current extension API surface:
asset-scoped `connect(assets?: SmirkAsset[])`, `getAddresses`,
`requestPayment`, and the `smirk-ready` WindowEventMap entry.
Per-asset return fields are nullable now since the user can approve
a subset of assets at connect time (cross-chain deanon mitigation).

src/app/page.tsx

@@ -26,13 +26,52 @@ export default function Home() {
   const [checkingSession, setCheckingSession] = useState(true);
   const [userCount, setUserCount] = useState<number | null>(null);
 
-  // Check for extension on mount
+  // Check for extension on mount.
+  //
+  // The Smirk extension injects via `<script type="module">`, which
+  // the browser DEFERS until after DOMContentLoaded — so a single
+  // immediate-or-500ms check could race past the injection on a busy
+  // Next.js page (the cause of an old "Connect" stays-greyed-out
+  // bug). Three layers cover all timings:
+  //
+  //   1. Immediate sync check (fast path: extension already there).
+  //   2. Listen for the `smirk-ready` CustomEvent (extension v0.2.5+).
+  //   3. Polling fallback up to ~3s, for older extensions + any
+  //      future browser quirk. Cheap; stops as soon as found.
   useEffect(() => {
-    const check = () => setHasExtension(!!window.smirk);
-    // Check immediately and after a delay (extension might inject late)
-    check();
-    const timeout = setTimeout(check, 500);
-    return () => clearTimeout(timeout);
+    let cancelled = false;
+    const found = () => {
+      if (!cancelled && window.smirk) {
+        setHasExtension(true);
+        return true;
+      }
+      return false;
+    };
+
+    // Layer 1: immediate.
+    if (found()) return;
+
+    // Layer 2: event from the extension (v0.2.5+).
+    const onReady = () => found();
+    window.addEventListener('smirk-ready', onReady);
+
+    // Layer 3: polling fallback (100ms intervals up to 3s).
+    const poll = setInterval(() => {
+      if (found()) clearInterval(poll);
+    }, 100);
+
+    // Final timeout: definitively mark as missing if still not seen.
+    const giveUp = setTimeout(() => {
+      clearInterval(poll);
+      if (!cancelled && !window.smirk) setHasExtension(false);
+    }, 3000);
+
+    return () => {
+      cancelled = true;
+      window.removeEventListener('smirk-ready', onReady);
+      clearInterval(poll);
+      clearTimeout(giveUp);
+    };
   }, []);
 
   // Fetch user count on mount

src/app/tip/[id]/TipPageClient.tsx

@@ -30,12 +30,38 @@ export default function TipPageClient({ tipId }: { tipId: string }) {
   const [claimError, setClaimError] = useState<string | null>(null);
   const [claimSuccess, setClaimSuccess] = useState<{ txid: string } | null>(null);
 
+  // Detect extension. See `app/page.tsx` for rationale — module-script
+  // injection is deferred, so we layer a sync check + smirk-ready
+  // event + 3s polling fallback.
   useEffect(() => {
-    // Check for extension
-    const check = () => setHasExtension(!!window.smirk);
-    check();
-    const timeout = setTimeout(check, 500);
-    return () => clearTimeout(timeout);
+    let cancelled = false;
+    const found = () => {
+      if (!cancelled && window.smirk) {
+        setHasExtension(true);
+        return true;
+      }
+      return false;
+    };
+
+    if (found()) return;
+
+    const onReady = () => found();
+    window.addEventListener('smirk-ready', onReady);
+
+    const poll = setInterval(() => {
+      if (found()) clearInterval(poll);
+    }, 100);
+    const giveUp = setTimeout(() => {
+      clearInterval(poll);
+      if (!cancelled && !window.smirk) setHasExtension(false);
+    }, 3000);
+
+    return () => {
+      cancelled = true;
+      window.removeEventListener('smirk-ready', onReady);
+      clearInterval(poll);
+      clearTimeout(giveUp);
+    };
   }, []);
 
   // Extract fragment key from URL

src/types/smirk.d.ts

@@ -1,15 +1,33 @@
-// TypeScript types for the Smirk extension's injected window.smirk API
+// TypeScript types for the Smirk extension's injected window.smirk API.
+//
+// Surface mirrors `smirk-extension/src/inject/smirk-api.ts`. Keep in
+// sync when the extension's API changes — when something doesn't
+// match here, the website breaks silently (the extension's actual
+// runtime is the source of truth, this file just lets us autocomplete).
 
+type SmirkAsset = 'btc' | 'ltc' | 'xmr' | 'wow' | 'grin';
+
+// Asset-scoped connect (extension v0.2.x onward) returns only the
+// approved assets — fields for un-approved assets are `null` rather
+// than missing, so callers can typecheck per-asset without rebinding.
 interface SmirkPublicKeys {
-  btc: string;
-  ltc: string;
-  xmr: string;
-  wow: string;
-  grin: string;
+  btc: string | null;
+  ltc: string | null;
+  xmr: string | null;
+  wow: string | null;
+  grin: string | null;
+}
+
+interface SmirkAddresses {
+  btc: string | null;
+  ltc: string | null;
+  xmr: string | null;
+  wow: string | null;
+  grin: string | null;
 }
 
 interface SmirkSignature {
-  asset: 'btc' | 'ltc' | 'xmr' | 'wow' | 'grin';
+  asset: SmirkAsset;
   signature: string;
   publicKey: string;
 }
@@ -25,16 +43,49 @@ interface SmirkClaimResult {
   error?: string;
 }
 
+interface SmirkPaymentRequest {
+  asset: 'btc' | 'ltc' | 'xmr' | 'wow';
+  amount: string;   // Atomic-units string (avoid float)
+  address: string;
+  memo?: string;
+}
+
+interface SmirkPaymentResult {
+  success: boolean;
+  txid?: string;
+  error?: string;
+}
+
 interface SmirkAPI {
   isSmirk: boolean;
-  connect(): Promise<SmirkPublicKeys>;
+  /**
+   * Connect to Smirk wallet — requests user approval to share public keys.
+   * @param assets Optional asset scope. If omitted, requests all assets.
+   *               Per-asset requests reduce metadata exposure (UI_DESIGN
+   *               Principle 7).
+   */
+  connect(assets?: SmirkAsset[]): Promise<SmirkPublicKeys>;
   disconnect(): Promise<void>;
   isConnected(): Promise<boolean>;
   getPublicKeys(): Promise<SmirkPublicKeys | null>;
+  getAddresses(): Promise<SmirkAddresses | null>;
   signMessage(message: string): Promise<SmirkSignResult>;
+  /**
+   * Request a payment from the user. Surfaces the Smirk send flow
+   * pre-filled with the asset/amount/address; user must approve.
+   */
+  requestPayment(request: SmirkPaymentRequest): Promise<SmirkPaymentResult>;
   claimPublicTip(tipId: string, fragmentKey: string): Promise<SmirkClaimResult>;
 }
 
+// CustomEvent fired on `window` when the extension finishes injecting
+// its API. Listen for this in your detection logic alongside an
+// initial sync check; the extension may inject before OR after your
+// listener mounts (module scripts defer until after DOMContentLoaded).
+interface WindowEventMap {
+  'smirk-ready': CustomEvent<void>;
+}
+
 interface Window {
   smirk?: SmirkAPI;
 }