Fix icons and add mirv to build bar (#2154)

## Description:

Fix blurry icons and add mirv to build bar
<img width="792" height="101" alt="image"
src="https://github.com/user-attachments/assets/a46c4724-c99b-4541-b56b-92ec662c8ec5"
/>

<img width="176" height="275" alt="image"
src="https://github.com/user-attachments/assets/dbcd2ed4-0f21-4065-9a52-9b16e9043270"
/>


## 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:

DISCORD_USERNAME

src/client/InputHandler.ts

@@ -188,9 +188,10 @@ export class InputHandler {
       buildDefensePost: "Digit4",
       buildMissileSilo: "Digit5",
       buildSamLauncher: "Digit6",
-      buildAtomBomb: "Digit7",
-      buildHydrogenBomb: "Digit8",
-      buildWarship: "Digit9",
+      buildWarship: "Digit7",
+      buildAtomBomb: "Digit8",
+      buildHydrogenBomb: "Digit9",
+      buildMIRV: "Digit0",
       ...saved,
     };
 
@@ -409,6 +410,11 @@ export class InputHandler {
         this.uiState.ghostStructure = UnitType.Warship;
       }
 
+      if (e.code === this.keybinds.buildMIRV) {
+        e.preventDefault();
+        this.uiState.ghostStructure = UnitType.MIRV;
+      }
+
       // Shift-D to toggle performance overlay
       console.log(e.code, e.shiftKey, e.ctrlKey, e.altKey, e.metaKey);
       if (e.code === "KeyD" && e.shiftKey) {