test cleanup: scrub planning-artifact identifiers from test names and section headers (suite-wide)

[michael-wojcik]

Background

Per pinned feedback_no_planning_artifact_test_names.md: test names describe behavior, not provenance; no T#/story#/ticket# prefixes. Pre-existing test files contain section headers and (potentially) test names that violate this rule with planning-artifact identifiers like be-F2, sec-M5, te-MED-1, arch2-M2, sec-F1, etc. These are tracker-style references to specific planning rounds, audit cycles, or finding IDs from prior work.

Surfaced by pact-test-engineer-620 review of PR #638 (docs/review/620-test-engineer-review.md, finding F3-te → relabeled F6 in synthesis).

Confirmed occurrences (incomplete)

In pact-plugin/tests/test_inbox_wake_lifecycle_emitter.py:

• L408 `# ---------- Terminal-status detection covers deleted (be-F2) ----------`
• L457 `# ---------- Lead-session guard (sec-M5 / te-MED-1) ----------`
• L523 `# ---------- Perf reorder (arch2-M2) ----------`
• L612 `# ---------- Stdin payload size limit (sec-F1) ----------`

Likely more across other test files; suite-wide scrub needed.

Scope

1. Grep across `pact-plugin/tests/**` for planning-artifact identifier patterns: `be-F\d`, `sec-[MF]\d`, `te-(MED|HIGH|LOW)`, `arch\d?-[MF]\d`, similar.
2. Rewrite section header comments and test names to describe BEHAVIOR, not planning-provenance.
3. If load-bearing context exists, move citations to a docstring or comment INSIDE the test, not the test name or section header.
4. Run full pact-plugin/tests/ to verify no behavior change.

Acceptance

• Grep for the patterns above returns zero matches in `pact-plugin/tests/`.
• Full test suite still passes.
• Section headers and test names describe what the test asserts, not which planning round added it.

Cross-references

• Pinned: `feedback_no_planning_artifact_test_names.md`
• Surfaced by: PR fix: extend _extract_task_id to probe nested tool_response.task.id (#620) #638 review (docs/review/620-test-engineer-review.md F3-te)

[michael-wojcik]

Additional known location surfaced during PR #638 remediation: pact-plugin/tests/test_inbox_wake_lifecycle_emitter.py:543 has an unused result = LHS in test_count_active_tasks_not_called_on_metadata_only_taskupdate (same pattern as the L582/L603 cases that were bundled into PR #638's commit f2c8b30). Deferred to this issue per "#640 is the suite-wide cleanup home" scope-discipline.