fix(engine): sync Zireael v1.3.6 + wide-glyph runtime hardening

[RtlZeroMemory]

Summary

• bump vendored Zireael to v1.3.6 (vendor/zireael gitlink + packages/native/vendor/VENDOR_COMMIT.txt)
• sync native vendored engine sources and include pins used by @rezi-ui/native
• harden diff/painter behavior for wide-glyph edge cases and non-ASCII cursor re-anchor (via vendored Zireael update)
• add Rezi-side icon glyph resolution fallback for risky Unicode glyphs and use measured resolved width for icon layout/render
• merge previous/current damage rect footprints in incremental path to avoid stale artifacts when content width changes
• expand native/core tests for these paths

Validation

• npm run build
• npm -w @rezi-ui/core run test
• cargo test (in packages/native)
• npm run check:unicode
• npm run lint
• npm run build:native
• npm run test:native:smoke (non-TTY skip path)