fix(cloud-frontend/login): correct BNB icon + i18n a handful of strings

### BNB icon

The EVM wallet button shows three chain icons in a row (Ethereum,
Base, BNB). The BNB glyph was rendering as a white disc with yellow
diamonds, which is not how the BNB Chain mark is drawn anywhere. The
brand spec and every reference rendering (bnbchain.org, Wikimedia
reference SVG, Brandfetch) use a yellow disc with the diamond pattern
in white.

Fix: wrap the diamond path in a yellow `<circle>` background and
recolor the diamonds white. The diamond geometry itself was already
correct (4 outer + 1 center, viewBox `0 0 32 32` centered on 16,16),
so only the fill colors and the surrounding disc had to change.

### i18n nits

A handful of user-facing strings in `steward-login-section.tsx`
shipped untranslated while every neighboring label uses `useT()`.
Bring them into the same translation surface so that locales can
override them and so the file is internally consistent:

  - Email input placeholder ("you@example.com")
  - Passkey button label ("Passkey")
  - Magic Link button label ("Magic Link")
  - "Redirecting to dashboard..." success state
  - "Loading sign-in options..." loading state (text + aria-label)

All new translation keys live under `cloud.login.*` and carry a
`defaultValue` matching the previous literal so existing
case-insensitive button-name selectors in `steward-login-section.test.tsx`
(`{ name: /passkey/i }`, `{ name: /magic link/i }`) continue to
resolve.

No behavior change. Typecheck + biome clean.

Author: 0xSolace

packages/cloud-frontend/src/pages/login/steward-login-section.tsx

@@ -388,7 +388,11 @@ export default function StewardLoginSection() {
     return (
       <div className="flex flex-col items-center gap-4 py-8">
         <div className="h-8 w-8 animate-spin rounded-full border-2 border-white border-t-transparent" />
-        <p className="text-sm text-white/72">Redirecting to dashboard...</p>
+        <p className="text-sm text-white/72">
+          {t("cloud.login.redirecting", {
+            defaultValue: "Redirecting to dashboard...",
+          })}
+        </p>
       </div>
     );
   }
@@ -422,10 +426,16 @@ export default function StewardLoginSection() {
         className="flex flex-col items-center gap-4 py-8"
         role="status"
         aria-busy="true"
-        aria-label="Loading sign-in options"
+        aria-label={t("cloud.login.loadingOptions.aria", {
+          defaultValue: "Loading sign-in options",
+        })}
       >
         <div className="h-8 w-8 animate-spin rounded-full border-2 border-white border-t-transparent" />
-        <p className="text-sm text-white/72">Loading sign-in options...</p>
+        <p className="text-sm text-white/72">
+          {t("cloud.login.loadingOptions", {
+            defaultValue: "Loading sign-in options...",
+          })}
+        </p>
       </div>
     );
   }
@@ -444,7 +454,9 @@ export default function StewardLoginSection() {
       <input
         ref={emailInputRef}
         type="email"
-        placeholder="you@example.com"
+        placeholder={t("cloud.login.emailPlaceholder", {
+          defaultValue: "you@example.com",
+        })}
         value={email}
         onChange={(e) => setEmail(e.target.value)}
         onKeyDown={(e) => {
@@ -463,7 +475,8 @@ export default function StewardLoginSection() {
             disabled={isLoading}
             className="flex flex-1 items-center justify-center gap-2 bg-[#FF5800] px-4 py-3 font-semibold text-white transition-colors hover:bg-[#FF5800]/85 disabled:opacity-50"
           >
-            {loading === "passkey" ? <Spinner /> : <PasskeyIcon />} Passkey
+            {loading === "passkey" ? <Spinner /> : <PasskeyIcon />}{" "}
+            {t("cloud.login.button.passkey", { defaultValue: "Passkey" })}
           </button>
         )}
         {providers.email !== false && (
@@ -473,7 +486,10 @@ export default function StewardLoginSection() {
             disabled={isLoading}
             className="flex flex-1 items-center justify-center gap-2 border border-white/30 bg-black/40 px-4 py-3 font-semibold text-white transition-colors hover:bg-white/10 disabled:opacity-50"
           >
-            {loading === "email" ? <Spinner /> : <EmailIcon />} Magic Link
+            {loading === "email" ? <Spinner /> : <EmailIcon />}{" "}
+            {t("cloud.login.button.magicLink", {
+              defaultValue: "Magic Link",
+            })}
           </button>
         )}
       </div>

packages/cloud-frontend/src/pages/login/wallet-buttons.tsx

@@ -364,15 +364,20 @@ function BaseIcon() {
 }
 
 function BnbIcon() {
+  // BNB Chain mark: yellow disc with the four-diamond + center-diamond
+  // pattern in white. Matches https://bnbchain.org brand guidelines and
+  // the Wikimedia reference SVG. Previously the disc was white with
+  // yellow diamonds, which is not how the mark is rendered anywhere.
   return (
     <svg
-      className="h-4 w-4 rounded-full bg-white ring-1 ring-black/20"
+      className="h-4 w-4 rounded-full ring-1 ring-black/20"
       aria-hidden="true"
       viewBox="0 0 32 32"
       xmlns="http://www.w3.org/2000/svg"
     >
+      <circle cx="16" cy="16" r="16" fill="#F0B90B" />
       <path
-        fill="#F0B90B"
+        fill="#FFFFFF"
         d="M16 4 11.3 8.7 16 13.4l4.7-4.7L16 4Zm-7.3 7.3L4 16l4.7 4.7L13.4 16 8.7 11.3Zm14.6 0L18.6 16l4.7 4.7L28 16l-4.7-4.7ZM16 18.6l-4.7 4.7L16 28l4.7-4.7L16 18.6Zm0-5.2L13.4 16 16 18.6 18.6 16 16 13.4Z"
       />
     </svg>