Login with Google — client UI (#4028) (#4279)

Resolves #4028 (client half — backend is openfrontio/infra#368, which
must be deployed first).

## Description:

Adds "Login with Google" to the client, alongside the existing Discord
login. Companion to the backend PR (openfrontio/infra#368).

- `Auth.ts` — `googleLogin()` (full-page redirect to
`/auth/login/google?redirect_uri=…`, mirrors `discordLogin()`).
- `ApiSchemas.ts` — `GoogleUserSchema` + optional `user.google` on
`UserMeResponseSchema`.
- `AccountModal.ts` — a "Login with Google" button (Google brand
guidelines: white surface, dark text, the multicolor "G" mark) in the
login options, and the logged-in view now renders a Google-authenticated
user's email (also added `google` to `isLinkedAccount()`).
- `en.json` — `main.login_google`.
- `resources/images/GoogleLogo.svg` — the Google "G" mark.

> **Draft.** Depends on infra#368 being deployed (the button hits the
live `/auth/login/google`).

## Please complete the following:

- [x] I have added screenshots for all UI updates <!-- TODO: add
screenshot of the Google button -->
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory <!-- no client
tests exist for AccountModal/Auth; verified via tsc --noEmit + eslint.
Backend behaviour is covered in infra#368 -->

## Please put your Discord username so you can be contacted if a bug or
regression is found:

jish

resources/images/GoogleLogo.svg

@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 48 48" aria-hidden="true">
+  <path fill="#EA4335" d="M24 9.5c3.54 0 6.71 1.22 9.21 3.6l6.85-6.85C35.9 2.38 30.47 0 24 0 14.62 0 6.51 5.38 2.56 13.22l7.98 6.19C12.43 13.72 17.74 9.5 24 9.5z"/>
+  <path fill="#4285F4" d="M46.98 24.55c0-1.57-.15-3.09-.38-4.55H24v9.02h12.94c-.58 2.96-2.26 5.48-4.78 7.18l7.73 6c4.51-4.18 7.09-10.36 7.09-17.65z"/>
+  <path fill="#FBBC05" d="M10.53 28.59c-.48-1.45-.76-2.99-.76-4.59s.27-3.14.76-4.59l-7.98-6.19C.92 16.46 0 20.12 0 24c0 3.88.92 7.54 2.56 10.78l7.97-6.19z"/>
+  <path fill="#34A853" d="M24 48c6.48 0 11.93-2.13 15.89-5.81l-7.73-6c-2.15 1.45-4.92 2.3-8.16 2.3-6.26 0-11.57-4.22-13.47-9.91l-7.98 6.19C6.51 42.62 14.62 48 24 48z"/>
+  <path fill="none" d="M0 0h48v48H0z"/>
+</svg>

resources/lang/en.json

@@ -12,7 +12,13 @@
     "failed_to_send_recovery_email": "Failed to send recovery email",
     "fetching_account": "Fetching account information...",
     "get_magic_link": "Get Magic Link",
+    "google_alt": "Google",
     "link_discord": "Link Discord Account",
+    "link_google": "Link Google Account",
+    "link_google_already_linked": "That Google account is already linked to another player.",
+    "link_google_error": "Couldn't link your Google account. Please make sure you're signed in and try again.",
+    "link_google_failed": "Couldn't start Google linking. Please try again.",
+    "link_google_success": "Google account linked.",
     "linked_account": "Logged in as {account_name}",
     "log_out": "Log Out",
     "manage_subscription": "Manage",
@@ -807,6 +813,7 @@
     "join": "Join Lobby",
     "leaderboard": "Leaderboard",
     "login_discord": "Login with Discord",
+    "login_google": "Login with Google",
     "menu": "Menu",
     "news": "News",
     "play": "Play",