Rewrite Overlay Layering Tests #789

Summary

Migrate overlay tests from DOM visibility checks to Phaser canvas occlusion/layering assertions.

Player and user experience impact

• Player experience: Card visuals remain visible and correctly occluded by overlays using Phaser layer/depth semantics.
• Developer experience: One consistent rendering path with reduced DOM-specific maintenance overhead.

Acceptance Criteria

• Help/settings layering tests assert canvas-native occlusion outcomes.
• No test depends on svgDom visibility toggling behavior.
• Main Street browser layering tests remain stable in CI.

Minimal Implementation (end-to-end slice)

• Rewrite tests/main-street/HelpPanelLayering.browser.test.ts assertions around occlusion/layer order.
• Update any related browser tests tied to DOM visibility behavior.
• Use resilient assertions that tolerate minor animation timing variance.

Dependencies

• Remove DOM Renderer Path
• Unify Shared SVG Texture Pipeline

Deliverables

• Updated browser tests
• Testing rationale notes

References

• Parent: Phaser-native rendering for DOM SVG card visuals (replace svgDom) (CG-0MP8YFNX4007N9ZU)