Slate v2 Phase 9 Highlight Matrix

Supporting plan. For current queue and roadmap truth, see master-roadmap.md.

Goal

Continue Phase 9 replacement-envelope expansion by widening the compatibility matrix for the highlight / decoration family.

Scope

• keep the existing legacy search-highlighting row
• add a current highlighted-text row
• sync the scoreboard/docs if the row lands cleanly

Constraints

• no fake direct parity claim between the old search UI and the current projection-driven highlight surface
• use the matrix to show the current family-level truth, not identical product shape
• verify through the cross-repo local runner on current port 3010

Progress

• added one current highlighted-text row to the replacement compatibility matrix
• proved the expanded matrix through the cross-repo local runner
• synced the scoreboard and top-level v2 docs so the landed Phase 9 slice is visible in the roadmap stack
• verification:
  • bash ./scripts/run-cross-repo-local.sh 3010 /examples/rich-inline ../slate 3210 /examples/search-highlighting "yarn build:slate-browser:playwright && yarn exec playwright test playwright/integration/examples/replacement-compatibility.test.ts --project=chromium --workers=1"