test: cover invest execution seam and ratchet coverage floors

[i-xtsu-sixyou-ken-mei]

Intent

Protect the app-level reviewed-invest execution seam and ratchet stale coverage floors to match the repository's current tested baseline.

Scope

• Add contract tests for InvestExecutionProvider reviewed execution.
• Cover missing/stale review groups, wallet switches, review-changed responses, exact reviewed transaction forwarding, risk/fingerprint forwarding, multi-batch progression, and draft invalidation.
• Ratchet coverage floors for apps/app, apps/control-center, packages/app-core, and apps/landing-page.
• Update scripts/COVERAGE.md with the new floors and measured 2026-09-08 baselines.

Product contract / invariants

• This PR does not change a product or execution invariant.
• Reviewed execution still signs only the exact server-reviewed batch and remains fail-closed on wallet/review drift.

Acceptance criteria

• App-level reviewed execution has direct contract coverage.
• Wallet/review drift never reaches the wallet executor.
• The exact transaction list and review fingerprints are asserted at the wallet boundary.
• Multi-batch execution advances one reviewed group at a time.
• Draft changes clear stale reviewed state.
• Four previously stale workspace coverage floors are materially higher while retaining roughly four points of churn buffer.

Coverage ratchet

Measured 2026-09-08 baseline → new floor:

• app: 68.34/71.50/72.63/69.10 → 64/67/68/65
• control-center: 81.84/70.36/82.05/82.06 → 77/66/78/78
• app-core: 79.71/70.58/77.91/80.86 → 75/66/73/76
• landing-page: 83.87/71.97/87.31/85.72 → 79/67/82/81

Order is statements / branches / functions / lines.

Validation

GitHub CI is the executable validation gate for this connector-authored branch. The PR is intended to run the full tests, coverage, code-quality and type-check gates before merge.

Out of scope

• Social release cohort compatibility cleanup.
• Generic simplification/refactoring.
• Raising unrelated workspace coverage floors.