fix: add missing OAuth i18n keys, remap dev redis off port 6379

login page referenced auth.continueWithGithub/Discord/Authentik keys that
didn't exist in en/fr message files, crashing the login page. Also remap
docker/compose.yml redis to 6380 since 6379 collides with an unrelated
local container on this machine.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/messages/en.json

@@ -168,6 +168,9 @@
     "signUpFailed": "Sign up failed",
     "signUpSuccess": "Account created — check your email to verify",
     "continueWithGoogle": "Continue with Google",
+    "continueWithGithub": "Continue with GitHub",
+    "continueWithDiscord": "Continue with Discord",
+    "continueWithAuthentik": "Continue with Authentik",
     "email": "Email",
     "emailPlaceholder": "you@example.com",
     "password": "Password",