Move attack troop overlay to WebGL (#3996)

## Description:

Replaces the DOM-based `AttackingTroopsOverlay` with
`AttackingTroopsController`, rendering attack troop counts through
`WorldTextPass` instead of a separate fixed-position DOM container.

## Summary

- New `AttackingTroopsController` polls `attackClusteredPositions()`
every 200ms and pushes labels to the WebGL view each frame, lerping
cluster positions over 250ms for smooth front-line movement (replaces
the old CSS `transform 0.25s` transition).
- `WorldTextPass` gains `setAttackTroopLabels()` and renders them at a
fixed on-screen size (zoom-independent) using `screenScale / zoom`.
- World text now draws on top of `NamePass` so attack callouts aren't
hidden behind centered player names.
- Fragment shader adds a soft quadratic dark halo around every
world-text label; extent uses the remaining SDF range after the hard
outline so it fades smoothly to zero (no rectangular clipping).
- Deletes `AttackingTroopsOverlay.ts`; existing unit tests repointed to
the controller's exported `alignClusterOrder`.

<img width="369" height="395" alt="Screenshot 2026-05-24 at 4 43 51 PM"
src="https://github.com/user-attachments/assets/4dbffe20-77f9-4c0f-b956-ecf543538f8d"
/>

## 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:

evan

src/client/render/gl/GameView.ts

@@ -30,6 +30,7 @@ import type {
   RadialMenuItem,
 } from "./Events";
 import type { SpawnCenter } from "./passes/SpawnOverlayPass";
+import type { AttackTroopLabel } from "./passes/WorldTextPass";
 import { GPURenderer } from "./Renderer";
 import type { RenderSettings } from "./RenderSettings";
 
@@ -289,6 +290,9 @@ export class GameView {
   applyConquestEvents(events: ConquestFx[]): void {
     this.renderer?.applyConquestEvents(events);
   }
+  setAttackTroopLabels(labels: AttackTroopLabel[]): void {
+    this.renderer?.setAttackTroopLabels(labels);
+  }
   applyBonusEvents(events: BonusEvent[]): void {
     this.renderer?.applyBonusEvents(events);
   }