feat: Implement compatibility bridge for legacy single-SVG callers

- Added compatibility lookups for legacy single-SVG callers to ensure existing workflows function during migration to new architecture.
- Implemented `getLayerSvg`, `getLayerSurface`, and `queryMap` functions as stable globals.
- Migrated relevant code in `draw-state-labels.ts` to utilize the new `queryMap` function for scene-aware lookups.
- Updated `layers.js` to manage layer visibility and registration more effectively.
- Introduced `LayersModule` to handle layer registration, visibility, and ordering.
- Created `WebGLSurfaceLayer` and `SvgLayer` classes to encapsulate layer behavior.
- Refactored `TextureAtlasLayer` to utilize the new layer management system.
- Updated HTML structure to accommodate new SVG and canvas elements.
- Ensured all TypeScript checks pass with zero errors on modified files.

_bmad-output/implementation-artifacts/sprint-status.yaml

@@ -43,8 +43,8 @@ development_status:
   epic-1: in-progress
   1-1-bootstrap-scene-container-and-defs-host: in-progress
   1-2-add-scene-module-for-shared-camera-state: in-progress
-  1-3-add-layers-registry-as-the-ordering-source-of-truth: ready-for-dev
-  1-4-add-layer-surface-lifecycle-ownership: ready-for-dev
+  1-3-add-layers-registry-as-the-ordering-source-of-truth: in-progress
+  1-4-add-layer-surface-lifecycle-ownership: done
   1-5-add-compatibility-lookups-for-legacy-single-svg-callers: ready-for-dev
   1-6-move-shared-defs-resources-to-the-dedicated-host: ready-for-dev
   epic-1-retrospective: optional