Show operator questions as an inset overlay

[TheGreatAxios]

Summary

• Shows operator questions through the inset overlay path so the transcript stays visible while choosing
• Keeps permission gates on the existing inset path and leaves full-shell overlay plumbing available for explicit callers
• Updates tests, comments, and unreleased notes to match the restored operator-question behavior

Verification

• bun test src/tui/overlays.test.ts -t "long body" fails before the implementation and passes after it
• bun test src/tui/overlays.test.ts passes
• bun run check reaches the full test suite but hits an unrelated prompt-contract false positive because this worktree path contains ask_operator; the same prompt test passes on origin/main

Fixes CL-7176

[linear-code]

CL-7176

[TheGreatAxios]

lens: critic
verdict: clean

This branch restores operator questions to the inset overlay path so the chat-first rationale remains visible while choosing. I found no blocking or should-fix defects. The only full gate caveat is the unrelated cwd-path prompt test false positive documented in the PR body.

[TheGreatAxios]

Review · Approve

openOperatorOverlay no longer forces overlayMode: "full_shell", so ask_operator questions open as an inset overlay with the transcript visible.

No findings.

Notes

• This reintroduces the 8-row DECISION_CONTEXT_ROWS clipping CL-7067 removed (pinned by src/tui/overlays.test.ts:283-286); CHANGELOG owns it as the trade-off and the prompt-side "short question, rationale in chat first" guidance from CL-7067 stays in place as the mitigation.
• full_shell plumbing in src/tui/shell.ts (relayoutOverlayHost, decisionContextBudget, OpenListOverlayOpts.overlayMode) now has no production caller — only overlays.test.ts:228. Follow-up deletion candidate.
• Checks: bun run typecheck, bun run lint, bun test src/tui/overlays.test.ts src/tui/landing.test.ts (44 pass). Full bun test: 2 failures, both reproduce on origin/main (src/prompts.test.ts:273 trips on the worktree path containing ask_operator; vendor/intx-inference/src/reactor.test.ts fails identically on main).