fix(L4): generate EIP-6963 provider UUID at install time

UUID is generated once via crypto.randomUUID(), persisted in
chrome.storage.local, and sent from the content script to the
inpage script via postMessage.

src/content/inpage.js

@@ -155,21 +155,36 @@
                 "</svg>",
         );
 
-    const providerInfo = {
-        uuid: "f3c5b2a1-8d4e-4f6a-9c7b-1e2d3a4b5c6d",
-        name: "AutistMask",
-        icon: ICON_SVG,
-        rdns: "berlin.sneak.autistmask",
-    };
+    let providerUuid = crypto.randomUUID(); // fallback until real UUID arrives
+
+    function buildProviderInfo() {
+        return {
+            uuid: providerUuid,
+            name: "AutistMask",
+            icon: ICON_SVG,
+            rdns: "berlin.sneak.autistmask",
+        };
+    }
 
     function announceProvider() {
         window.dispatchEvent(
             new CustomEvent("eip6963:announceProvider", {
-                detail: Object.freeze({ info: providerInfo, provider }),
+                detail: Object.freeze({
+                    info: buildProviderInfo(),
+                    provider,
+                }),
             }),
         );
     }
 
+    // Listen for the persisted UUID from the content script
+    window.addEventListener("message", (event) => {
+        if (event.source !== window) return;
+        if (event.data?.type !== "AUTISTMASK_PROVIDER_UUID") return;
+        providerUuid = event.data.uuid;
+        announceProvider();
+    });
+
     window.addEventListener("eip6963:requestProvider", announceProvider);
     announceProvider();
 })();