harden: end a site's unremembered connection when its address or wallet is removed (closes #245)

A site connected without "Remember" lives only in the background's
in-memory connectedSites map. Removing an address or deleting a wallet
dropped the remembered permissions but never told the background; the
entry went only as a side effect of the accountsChanged broadcast, which
empties the whole map when the active address changes.

dropSitePermissions(), shared by both removal paths, now sends
AUTISTMASK_ADDRESSES_REMOVED with the removed addresses, and the
background deletes their entries. Only the extension's own pages may
send it.

Model: opus-5-5

tests/backgroundApproval.test.js

@@ -25,6 +25,10 @@ const { Network, Wallet } = require("ethers");
 // what the user is actually shown.
 const { describeSigningFailure } = require("../src/shared/approvalVerify");
 const { makeStorageStub } = require("./support/storageStub");
+const {
+    removeAddressFromState,
+    removeWalletFromState,
+} = require("../src/shared/walletDelete");
 
 const SIGNER_KEY =
     "0x59c6995e998f97a5a0044966f0945389dc9e86dae88c7a8412f4603b6b78690d";
@@ -2096,3 +2100,95 @@ describe("a site connection decided as the popup closes", () => {
         });
     });
 });
+
+// A site connected without "Remember" is held only in the background's memory,
+// keyed to the address it was connected to. Removing that address, or the
+// wallet holding it, must end the connection as part of the removal itself.
+// The accountsChanged broadcast the views send afterwards also clears it, but
+// only when the active address moved, and nothing waits for it to arrive.
+//
+// Each test asks the background while storage still names the removed address
+// as active, because the popup has not saved yet, so the answer turns on the
+// connection alone.
+describe("removing an address ends a site's connection to it", () => {
+    // FRESH_ORIGIN connected to the active address without "Remember", in a
+    // wallet holding a second address so that one can be removed at all. The
+    // popup's messages reach the background as they would from the popup.
+    async function connectedBackground() {
+        const bg = loadBackground({ actionPopup: true });
+        const stored = bg.storage.read("autistmask");
+        stored.wallets[0].addresses.push({
+            address: other.address,
+            balance: "0",
+            tokenBalances: [],
+        });
+        bg.storage.write("autistmask", stored);
+
+        const pending = bg.requestSite();
+        await settle();
+        bg.connectApproval(pending.id()).decide(true, false);
+        await settle();
+        expect(pending.result()).toEqual({ result: [signer.address] });
+
+        global.chrome.runtime.sendMessage = (msg) => {
+            bg.send(msg, bg.fromPopup);
+        };
+        return bg;
+    }
+
+    // What FRESH_ORIGIN is told when it asks which account it may use.
+    async function siteAccounts(bg) {
+        const { sendResponse } = bg.send(
+            { type: "AUTISTMASK_RPC", method: "eth_accounts", params: [] },
+            { origin: FRESH_ORIGIN },
+        );
+        await settle();
+        return sendResponse.mock.calls[0][0];
+    }
+
+    test("removing the connected address ends the connection", async () => {
+        const bg = await connectedBackground();
+        expect(await siteAccounts(bg)).toEqual({ result: [signer.address] });
+
+        const popupState = bg.storage.read("autistmask");
+        expect(removeAddressFromState(popupState, 0, 0).removed).toBe(true);
+
+        expect(await siteAccounts(bg)).toEqual({ result: [] });
+    });
+
+    test("deleting the wallet holding the connected address ends the connection", async () => {
+        const bg = await connectedBackground();
+        expect(await siteAccounts(bg)).toEqual({ result: [signer.address] });
+
+        const popupState = bg.storage.read("autistmask");
+        removeWalletFromState(popupState, 0);
+
+        expect(await siteAccounts(bg)).toEqual({ result: [] });
+    });
+
+    test("removing a different address leaves the connection alone", async () => {
+        const bg = await connectedBackground();
+
+        const popupState = bg.storage.read("autistmask");
+        expect(removeAddressFromState(popupState, 0, 1).removed).toBe(true);
+
+        expect(await siteAccounts(bg)).toEqual({ result: [signer.address] });
+    });
+
+    test("a page cannot end the connection", async () => {
+        const bg = await connectedBackground();
+
+        const spoof = bg.send(
+            {
+                type: "AUTISTMASK_ADDRESSES_REMOVED",
+                addresses: [signer.address],
+            },
+            { url: FRESH_ORIGIN + "/index.html" },
+        );
+
+        expect(spoof.sendResponse).toHaveBeenCalledWith({
+            error: "Unauthorized sender",
+        });
+        expect(await siteAccounts(bg)).toEqual({ result: [signer.address] });
+    });
+});