fix(compose): hide flattened semantics descendants

[bytemain]

Summary

• preserve the unmerged semantics ancestry beneath clearAndSetSemantics
• project an invisible ancestor's hidden role to every real descendant KNode, covering flattened native view hierarchies
• restore visible descendants through the existing per-generation merged projection/registry
• add synthetic flattened-tree and visible-restoration regressions

Root cause

The landed Android APK uniquely contained and executed the #93 role/testTag fix: both setters resolve hidden to IMPORTANT_FOR_ACCESSIBILITY_NO_HIDE_DESCENDANTS. Runtime still exposed an AccessibilityNodeInfo parent/child tree byte-identical to the old build. The semantics hierarchy shown by AccessibilityNodeInfo is therefore not the Android ViewGroup hierarchy: Kuikly flattens descendant KNodes, so hiding only the semantic root View cannot prune the real descendant Views.

This change only projects AccessibilityRole.HIDDEN; it does not clear text/click semantics. Android maps that role to NO_HIDE_DESCENDANTS, while iOS/OHOS remain outside this patch's native-bridge scope.

Validation

• focused Compose projection and Android importance tests
• broad Compose tests + common metadata compile + Android renderer tests
• git diff --check