Feat: Alliance and betrayal hotkeys (#3110)

Original Feature request by @FloPinguin  
Resolves #3077 

## Description:

Adds hotkeys for Requesting alliances and breaking alliances. This
allows for players to send or break alliances whose tile is under the
cursor, without opening the radial menu.

Keybinds:
New "Ally Keybinds" section in Settings -> Keybinds
Request alliance: Default: K - sends an alliance request to the
player/bot/nation under the cursor
Break alliance: Default: L - breaks the alliance with the player at the
cursor

Behavior:
- Cursor must be over a tile owned by the target player. The action runs
only when the game allows it, following the same logic as the radial
menu. (canSendAllianceRequest and canBreakAlliance)
- When an alliance request is sent, the events log shows: "Alliance
request sent to [target]" for confirmation. No extra message for
breaking an alliance (betrayal/debuff message already exists and is sent
upon breaking an alliance)

## Screenshots:
Keybind menu:
<img width="739" height="595" alt="image"
src="https://github.com/user-attachments/assets/ee958eab-fd50-4971-85c5-dfd49c6f0bdc"
/>
In game logs:
<img width="373" height="232" alt="image"
src="https://github.com/user-attachments/assets/2cf6bb07-5f0d-425a-82d3-65a44fef99c5"
/>

## 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
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced


Discord username:
_Dave9595_

src/client/UserSettingModal.ts

@@ -657,6 +657,32 @@ export class UserSettingModal extends BaseModal {
         @change=${this.handleKeybindChange}
       ></setting-keybind>
 
+      <h2
+        class="text-blue-200 text-xl font-bold mt-8 mb-3 border-b border-white/10 pb-2"
+      >
+        ${translateText("user_setting.ally_keybinds")}
+      </h2>
+
+      <setting-keybind
+        action="requestAlliance"
+        label=${translateText("user_setting.request_alliance")}
+        description=${translateText("user_setting.request_alliance_desc")}
+        defaultKey="KeyK"
+        .value=${this.getKeyValue("requestAlliance")}
+        .display=${this.getKeyChar("requestAlliance")}
+        @change=${this.handleKeybindChange}
+      ></setting-keybind>
+
+      <setting-keybind
+        action="breakAlliance"
+        label=${translateText("user_setting.break_alliance")}
+        description=${translateText("user_setting.break_alliance_desc")}
+        defaultKey="KeyL"
+        .value=${this.getKeyValue("breakAlliance")}
+        .display=${this.getKeyChar("breakAlliance")}
+        @change=${this.handleKeybindChange}
+      ></setting-keybind>
+
       <h2
         class="text-blue-200 text-xl font-bold mt-8 mb-3 border-b border-white/10 pb-2"
       >