fix(planning): have export-ledger emit a confirmation recap that fits the restatement cap #7759

Parent

Refs #5893

Depends on

• none: on the frontier now

Outcome

A long interview's confirmation recap passes the restatement cap without hand-trimming. The confirmation gate asks for one recap line per question in decisions, generated from export-ledger; with 128 ids that recap was 43,897 characters and apply refused it against the 20,000-character cap, so the session collapsed withdrawn rows and truncated answers by hand. export-ledger emits the compact form itself.

Owner decision recorded on #5893 (2026-10-12): "Item 4: where does the compact confirmation recap come from?" → export-ledger emits a compact recap that fits the cap.

Key interfaces

• round.py: cmd_export_ledger and the restate section cap (TEXT_CAP).
• Interview skill surface.md Confirmation gate.

Done when

• A fixture with 128 ids (79 withdrawn) produces a recap from export-ledger that apply accepts under the cap (test).
• Every live question still has its own recap line; withdrawn rows are collapsed and long answers truncated (test).
• The Confirmation gate in surface.md names the exporter's compact form.
• The planning Python and surface test suites pass.

Out of scope

• Raising the cap.