Configurable immunity timer (#2763)

## Description:

Resolve discussions about stalled PR
https://github.com/openfrontio/OpenFrontIO/pull/2460

<img width="724" height="348" alt="image"
src="https://github.com/user-attachments/assets/c2c9fa79-cace-431a-9ca4-b3656612fa9d"
/>

Changes:
- Added a `Player::canAttackPlayer(other)` function to determine whether
a player can be attacked.
- This function is now used in most places where a fight can occur:
    - AttackExecution (land attacks)
    - Naval invasion
    - Warship fight
- Nukes can't be thrown during the truce
- Immunity only affect human players. Nations and bot will fight as
usual, and can be fought against.
- The immunity timer uses minutes in the modal window.

UI:

- The immunity phase is displayed with a timer bar at the top. This is
from the original PR, to be discussed if it's not deemed visible enough:

<img width="632" height="215" alt="image"
src="https://github.com/user-attachments/assets/f5ab9aa0-bd4f-4503-b8d6-b40b121fba65"
/>


## 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

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

IngloriousTom

---------

Co-authored-by: newyearnewphil <git@nynp.dev>

src/core/execution/AttackExecution.ts

@@ -92,16 +92,9 @@ export class AttackExecution implements Execution {
       }
     }
 
-    if (this.target.isPlayer()) {
-      if (
-        this.mg.config().numSpawnPhaseTurns() +
-          this.mg.config().spawnImmunityDuration() >
-        this.mg.ticks()
-      ) {
-        console.warn("cannot attack player during immunity phase");
-        this.active = false;
-        return;
-      }
+    if (this.target.isPlayer() && !this._owner.canAttackPlayer(this.target)) {
+      this.active = false;
+      return;
     }
 
     this.startTroops ??= this.mg

src/core/execution/TransportShipExecution.ts

@@ -93,6 +93,10 @@ export class TransportShipExecution implements Execution {
     } else {
       this.target = mg.player(this.targetID);
     }
+    if (this.target.isPlayer() && !this.attacker.canAttackPlayer(this.target)) {
+      this.active = false;
+      return;
+    }
 
     this.startTroops ??= this.mg
       .config()

src/core/execution/WarshipExecution.ts

@@ -89,7 +89,7 @@ export class WarshipExecution implements Execution {
       if (
         unit.owner() === this.warship.owner() ||
         unit === this.warship ||
-        unit.owner().isFriendly(this.warship.owner(), true) ||
+        !this.warship.owner().canAttackPlayer(unit.owner(), true) ||
         this.alreadySentShell.has(unit)
       ) {
         continue;