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# Session 04: Battlefield State and Interaction Polish

**Session ID**: `phase02-session04-battlefield-state-and-interaction-polish` **Package**: apps/web **Status**: Completed **Validated**: 2026-05-29 **Estimated Tasks**: \~16-24 **Estimated Duration**: 2-4 hours

***

## Objective

Finish app-side 2D battlefield state rendering, interaction behavior, accessibility, reduced motion, and visual recovery paths.

***

## Scope

### In Scope (MVP)

* Review `Battlefield.tsx`, `battlefield2d.ts`, achievement celebration behavior, CSS state classes, and tests.
* Tighten hero hit targets, selection labels, empty-board deselection, state rings, and failed-asset fallbacks.
* Verify active, awaiting input, verifying, error, spawning, dismissed, selected, and idle visual states.
* Preserve reduced-motion behavior while keeping static status information visible.
* Add focused tests for battlefield states, accessibility names, and fallback rendering.

### Out of Scope

* Reintroducing Three.js, WebGL, canvas physics, or 3D assets.
* Creating new gameplay-loop infrastructure.
* Replacing the approved battlefield art set unless validation proves a blocker.

***

## Prerequisites

* [ ] Session 01 requirements are complete.
* [ ] Existing battlefield tests are passing.

***

## Deliverables

1. Completed battlefield interaction and state treatment.
2. Focused battlefield component and helper tests.
3. Reduced-motion and fallback validation notes.
4. Updated battlefield docs for any changed behavior.

***

## Success Criteria

* [ ] Battlefield controls are accessible native controls with stable names and selected state.
* [ ] Visual state treatment is readable and recoverable across expected runtime states.
* [ ] Reduced-motion users retain status information without looping effects.
* [ ] Tests cover critical state and interaction regressions.


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