Skip empty textContent clear visual work #565

Parent: #243. CSS/performance epic: #235.

Proven hot path

Pinned unchanged Code OSS repeatedly clears absent/reused row and panel fields with empty textContent: virtualized action-list badge/description/group/detail, shared DOM reset, icon-label mode switches and SCM graph containers. WebScene still scheduled recascade/layout/publication when an ordinary Element/DocumentFragment already had no children or text.

Scope

After author ToString conversion and CharacterData handling, return for exact empty text assigned to an already-empty ordinary Element or DocumentFragment. Exclude style elements because CSSOM state may exist without DOM children. Preserve every real removal/replacement, author conversion, focus/selection, adoption, mutation and custom-element lifecycle path.

Acceptance

• Focused source and regression authored.
• git diff --check passes.
• 4,096 connected plus 4,096 detached redundant clears preserve identity/order/lifecycle/focus/selection/:empty style/node count with zero recascade/layout/publications.
• Populated controls prove exact real clear/detach/reattach/restoration and low-memory reclamation.
• Code OSS A/B/ABBA, browser/package, future MutationObserver, pixel, physical-performance and memory gates run later.

No build, test, benchmark or formatter was executed.