harden: lost-password confirmation refuses empty input and ignores invisible characters (closes #336)

A wallet named only with spaces compared equal to an empty field, so
typing nothing would have deleted it, and a zero-width space in a name
made the name impossible to type back.

An empty typed confirmation is now refused whatever the name is. The
characters src/shared/symbolSpoof.js already defines as painting nothing
are removed from both sides before comparing. A name that shows nothing
at all is shown on the delete screens as "Wallet N", so it can still be
typed back.

Model: opus-5-5

tests/deleteWalletLostPassword.test.js

@@ -46,6 +46,9 @@ const A1 = "0xdAC17F958D2ee523a2206206994597C13D831ec7";
 const B0 = "0x2260FAC5E5542a773Aa44fBCfeDf7C193bc2C599";
 const C0 = "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48";
 
+// U+200B, built from its code point so that it can be seen in this file.
+const ZERO_WIDTH_SPACE = String.fromCodePoint(0x200b);
+
 // ------------------------------------------------------------ DOM stub
 
 function makeElement(id) {
@@ -342,6 +345,72 @@ describe("the typed confirmation", () => {
             "secret-three",
         ]);
     });
+
+    // A name of only spaces compares as nothing, and so does an empty
+    // field. Typing nothing must still delete nothing.
+    test.each(["", "   "])(
+        "typing %j deletes nothing when the name is only spaces",
+        async (typedValue) => {
+            const { deleteWallet, state, storage } = load();
+            state.wallets[1].name = "   ";
+            await openLostPassword(deleteWallet, 1);
+
+            node("delete-wallet-lost-name-input").value = typedValue;
+            await click("btn-delete-wallet-lost-confirm");
+
+            expect(node("delete-wallet-lost-flash").style.visibility).toBe(
+                "visible",
+            );
+            expect(state.wallets).toHaveLength(3);
+            expect(await persistedWallets(storage)).toHaveLength(3);
+        },
+    );
+
+    // A name that shows nothing would leave nothing on screen to type
+    // back, so the screen names the wallet by its position instead, and
+    // that is what the user types.
+    test.each([
+        ["spaces", "   "],
+        ["a zero-width space", ZERO_WIDTH_SPACE],
+    ])(
+        "a name of only %s is shown and typed back as Wallet 2",
+        async (_label, storedName) => {
+            const { deleteWallet, state, storage } = load();
+            state.wallets[1].name = storedName;
+            await openLostPassword(deleteWallet, 1);
+
+            expect(node("delete-wallet-lost-name").textContent).toBe(
+                "Wallet 2",
+            );
+            node("delete-wallet-lost-name-input").value = "Wallet 2";
+            await click("btn-delete-wallet-lost-confirm");
+
+            const persisted = await persistedWallets(storage);
+            expect(persisted.map((w) => w.encryptedSecret)).toEqual([
+                "secret-one",
+                "secret-three",
+            ]);
+        },
+    );
+
+    // A zero-width space paints nothing, so "My", a zero-width space and
+    // "Wallet" reads as "MyWallet", and that is all the user can type. HTML
+    // does not collapse it the way it collapses spaces, so it has to be
+    // removed explicitly.
+    test("a zero-width space inside the name is not part of it", async () => {
+        const { deleteWallet, state, storage } = load();
+        state.wallets[1].name = "My" + ZERO_WIDTH_SPACE + "Wallet";
+        await openLostPassword(deleteWallet, 1);
+
+        node("delete-wallet-lost-name-input").value = "MyWallet";
+        await click("btn-delete-wallet-lost-confirm");
+
+        const persisted = await persistedWallets(storage);
+        expect(persisted.map((w) => w.encryptedSecret)).toEqual([
+            "secret-one",
+            "secret-three",
+        ]);
+    });
 });
 
 describe("deleting without the password", () => {