mweinbach4/19/2026, 1:47:33 AM

This closes the remaining PR #83 cap-handling regressions in the A2UI
surface manager. Rejected oversized updates now keep the last valid
surface revision instead of dropping server-side state, and oversized
createSurface requests no longer evict an older surface before the new
surface is proven acceptable.

Constraint: Overflow guards must keep server and client A2UI state in sync under the 256 KiB cap
Rejected: Emit synthetic delete events on rejected overflow updates | hides the real bug and still destroys a previously valid surface
Confidence: high
Scope-risk: narrow
Reversibility: clean
Directive: Any future cap-handling change must preserve rollback semantics for updates and validate new surfaces before eviction
Tested: bun test test/a2ui/surfaceManager.test.ts; bun run typecheck; bun test --max-concurrency 1
Not-tested: GitHub Actions on the new commit

Parent567686b