L4: generate per-install EIP-6963 provider UUID

Replace the hardcoded UUID with a per-install UUID generated via
crypto.randomUUID() and persisted in chrome.storage.local. The content
script sends the UUID to the inpage script via postMessage, which
updates providerInfo and re-announces the provider.

src/content/inpage.js

@@ -156,7 +156,7 @@
         );
 
     const providerInfo = {
-        uuid: "f3c5b2a1-8d4e-4f6a-9c7b-1e2d3a4b5c6d",
+        uuid: crypto.randomUUID(),
         name: "AutistMask",
         icon: ICON_SVG,
         rdns: "berlin.sneak.autistmask",
@@ -170,6 +170,15 @@
         );
     }
 
+    // Accept a stable per-install UUID from the content script.
+    // Re-announce with the updated providerInfo so dApps see the correct UUID.
+    window.addEventListener("message", (event) => {
+        if (event.source !== window) return;
+        if (event.data?.type !== "AUTISTMASK_PROVIDER_UUID") return;
+        providerInfo.uuid = event.data.uuid;
+        announceProvider();
+    });
+
     window.addEventListener("eip6963:requestProvider", announceProvider);
     announceProvider();
 })();