Unit menu (#867)

## Description:
We are adding a modal to display information about a unit.
![スクリーンショット 2025-05-25 7 45
14](https://github.com/user-attachments/assets/736262cd-6070-4a27-b58c-e85f9a02df75)

In the future, this modal will likely include buttons for upgrading or
dismantling the unit.
## Please complete the following:

- [x] 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:
aotumuri

src/core/execution/MissileSiloExecution.ts

@@ -53,7 +53,8 @@ export class MissileSiloExecution implements Execution {
       }
     }
 
-    if (this.silo.ticksLeftInCooldown() === 0) {
+    const cooldown = this.silo.ticksLeftInCooldown();
+    if (typeof cooldown === "number" && cooldown >= 0) {
       this.silo.touch();
     }
   }

src/core/execution/SAMLauncherExecution.ts

@@ -149,8 +149,8 @@ export class SAMLauncherExecution implements Execution {
       target = this.getSingleTarget();
     }
 
-    if (this.sam.ticksLeftInCooldown() === 0) {
-      // Touch SAM to update sprite to show not in cooldown.
+    const cooldown = this.sam.ticksLeftInCooldown();
+    if (typeof cooldown === "number" && cooldown >= 0) {
       this.sam.touch();
     }