orca/docs/split-groups-rollout-pr5.md

Split Groups PR 5: Hook Group Surfaces Into Flagged Path

This branch wires terminal, editor, and browser surfaces into the split-group ownership path inside Terminal.tsx, but holds that path behind a temporary local gate.

Scope:

• remove duplicate legacy ownership under the flagged path
• route group-local surface creation and restore through the new model
• preserve existing default behavior while the flag stays off

What Is Actually Hooked Up In This PR:

• Terminal.tsx now contains the real split-group surface path
• the new path mounts TabGroupSplitLayout and avoids keeping duplicate legacy surfaces mounted underneath
• the old legacy surface path is still present as the active runtime path in this branch

What Is Not Hooked Up Yet:

• the split-group path is still disabled by the temporary local rollout gate in Terminal.tsx
• users should still get legacy behavior by default in this branch