Discord (#4367)

Resolves #(issue number)

## Description:

continuation of https://github.com/openfrontio/infra/pull/359
adds ability to put discord URL into a dedicated slot 

pc:
<img width="1917" height="921" alt="image"
src="https://github.com/user-attachments/assets/100a25d5-e998-4744-904e-df40b74ccd76"
/>

mobile:
<img width="385" height="826" alt="image"
src="https://github.com/user-attachments/assets/de904f83-c88f-41e7-9c98-81c2296ec9a2"
/>


## Please complete the following:

- [x] I have added screenshots for all UI updates
- [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

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

w.o.n

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

resources/lang/en.json

@@ -181,6 +181,16 @@
     "deny": "Deny",
     "description": "Description",
     "disband_clan": "Disband Clan",
+    "discord_default_name": "Discord",
+    "discord_expires": "That invite expires, use one set to never expire.",
+    "discord_invalid": "That isn't a valid Discord invite link.",
+    "discord_invite_unavailable": "This Discord invite is no longer valid.",
+    "discord_online_members": "{online, number} online · {members, number} members",
+    "discord_rate_limited": "Please wait a minute before verifying another Discord link.",
+    "discord_section_title": "Discord",
+    "discord_url_hint": "Use an invite set to never expire.",
+    "discord_url_label": "Discord Invite URL",
+    "discord_url_placeholder": "https://discord.gg/...",
     "error_already_member": "Already a member",
     "error_banned": "You are banned from this clan.",
     "error_banned_reason": "You are banned from this clan. Reason: {reason}",
@@ -252,6 +262,7 @@
     "open": "Open",
     "open_clan": "Open Clan",
     "open_clan_desc": "Anyone can join without an invite",
+    "open_discord": "Open Discord",
     "pending_applications": "Pending Applications",
     "pending_requests_count": "{count, plural, one {# pending request} other {# pending requests}}",
     "per_page": "Per page",