Add Duration to Defense Debuff Messages (#603)

## Description:

This PR updates the in-game defense debuff message to include the
**duration** of the effect, improving clarity and usability during
gameplay.

### Change Summary:
- Updated static text to:  
`You broke your alliance with United States, making you a TRAITOR (50%
defense debuff for 30 secs)`
- Improves player understanding of how long penalties last.
- Aligns with other UI efforts focused on real-time feedback and clearer
mechanics.
- Sets a standard for future status/debuff messages to include duration
info where relevant.

This small but high-impact change enhances the player experience,
especially in intense or competitive matches where timing matters.

---

## Please complete the following:

- [] I have added screenshots for all UI updates  
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

---

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

**@walker9607**


Resolves issue
https://github.com/openfrontio/OpenFrontIO/issues/602#issue-3018752308

src/client/graphics/layers/EventsDisplay.ts

@@ -271,10 +271,19 @@ export class EventsDisplay extends LitElement implements Layer {
       const malusPercent = Math.round(
         (1 - this.game.config().traitorDefenseDebuff()) * 100,
       );
+      const traitorDurationRaw =
+        Number(this.game.config().traitorDuration) / 10;
+      const traitorDurationSeconds = Math.floor(traitorDurationRaw);
+
+      const durationText =
+        traitorDurationSeconds === 1
+          ? "1 second"
+          : `${traitorDurationSeconds} seconds`;
+
       this.addEvent({
         description:
           `You broke your alliance with ${betrayed.name()}, making you a TRAITOR ` +
-          `(${malusPercent}% defense debuff)`,
+          `(${malusPercent}% defense debuff for ${durationText})`,
         type: MessageType.ERROR,
         highlight: true,
         createdAt: this.game.ticks(),