Fix ~19 pre-existing failing tests on main (verifier/migrate-body/redact/plan-handoff harness drift)

main is currently red on ~19 tests that are unrelated to the recurring-bug-fix batch (merge 5136f3d8). They were verified pre-existing: the integration capstone ran the identical set against a pristine pre-batch main and got byte-identical failures, and every failing test file + its source-under-test is unchanged by the batch. This task tracks fixing them so main is green.

Failing clusters (as of 2026-05-28, uv run pytest)

1. tests/test_verify_clean_result.py (10) — test_good_body_passes, test_missing_subsection_fails, test_sample_outputs_too_few_fenced_blocks_fails, test_canonical_template_sample_outputs_passes, test_methodology_bullets_present_passes, test_methodology_prose_fails_strict_post_cutoff, test_methodology_prose_passes_pre_cutoff, test_background_motivation_present_passes, test_two_figures_both_captioned_passes, test_caption_multiline_html_comment_does_not_leak. The clean-result body verifier (verify_clean_result.py) and its fixtures have drifted apart (the new markdown clean-result spec moved checks around). Decide per-test whether the verifier or the fixture/expectation is stale.

2. tests/test_task_workflow.py::test_migrate_body_* (6) — test_migrate_body_classify_pass, _conformant_failing_remediation, _dry_run_does_not_write, _idempotency, _pass_body_is_noop, _report_classification. classify_body returns CONFORMANT_FAILING for a fixture the test expects to PASS — the migrate-body classifier drifted from the current spec.

3. tests/test_redact_for_gist.py (2) — test_full_fixture_redacted, test_idempotent. Redaction output no longer matches the expected fixture.

4. tests/test_plan_handoff_path_convention.py::test_claude_md_contains_plan_handoff_rule (1) — asserts the literal string 'Plan handoff convention' appears in CLAUDE.md, but the actual rule is worded **Plan handoff:**. Either reword the rule or relax the test's expected string.

(test_hub.py::test_upload_file and test_step_completed_resume.py were on the earlier pre-batch list but now PASS — test_hub via the data-eval mock fix that merged; recount before starting.)

Scope / approach

• For each cluster, determine whether the TEST or the SOURCE is stale (the spec churned — verifier checks 6→11→16, Lens 11/12/13, check 11b — so several are likely test-fixture drift, not real regressions). Fix the side that's wrong; do not just delete tests.
• tests/test_data_validation.py had a collection error (ModuleNotFoundError: explore_persona_space.data) on the pre-batch list — confirm whether that module is intended to exist or the test is obsolete.
• Acceptance: uv run pytest tests/ green (excluding any genuinely-obsolete tests that are removed with justification).

Provenance

Surfaced by the recurring-bug-fix workflow's integration capstone (2026-05-28); split out as a separate task because it predates and is orthogonal to that batch.