fix(rollups): stabilize tied monthly themes and partial-month wording

[jmservera]

Publication blocker

Source-only fix for the valid review on #831: #831 (comment).

• Count each tag once per week; rank by descending count, then tag name (including single-week synthesis and the top-five cutoff).
• Bump synthesis version to invalidate already-cached nondeterministic output; downstream monthly/yearly consumers use the same ordered themes.
• Replace October chapter wording "By month end" with "By the latest weekly report" so a partial month is not presented as finished.
• Regression covers real rendered synthesis across PYTHONHASHSEED 1, 2, 7, 42, 101; tied counts, duplicate tags, count priority, top-five selection, cache invalidation/reuse, and October wording.

Validation

• python3 -m ruff check .: passed
• python3 -m ruff format --check .: 212 files passed
• Affected synthesis/pipeline/yearly-evidence/sync tests: 99 passed
• Full python3 -m pytest -q tests/: 2030 passed, 1 existing skip
• git diff --check: passed

No generated artifacts changed. After source merge, production recovery must regenerate rollups on the data branch and verify the artifact before resolving the original data-review thread. Original PR831 thread remains unresolved intentionally. W42 video remains waiting; this PR does not authorize it.

Independent review is being arranged by the coordinator. Do not merge before latest-head CI, completed Copilot review, resolved source-PR threads, and that independent reviewer gate.

[Copilot]

🟢 Approval recommended

The focused implementation resolves the reported nondeterminism and includes comprehensive regression coverage.

0 open findings

What changed in this PR

Fixes the nondeterministic monthly rollup behavior reported in PR #831 and corrects partial-month yearly wording.

Changes:

• Deterministically ranks deduplicated weekly themes and invalidates stale synthesis caches.
• Rewords partial-month transitions.
• Adds regression coverage for ordering, hash seeds, caching, and wording.

File	Description
scripts/​month_synthesis.py	Stabilizes theme ordering and bumps the cache version.
scripts/​generate_yearly_narrative.py	Avoids implying the current month has ended.
tests/​test_generate_rollups.py	Covers deterministic output, cache refresh, and October wording.

🧠 Review effort: Balanced

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[jmservera]

READY FOR INDEPENDENT REVIEW at head 1e8c5bd064d8c1c3f557b3eed4f4a5e9ade8cd55.

All 18 latest-head checks passed, including Python/Ruff, lockfile, hydration parity, CodeQL/Bandit/Checkov/Zizmor, production build, Axe/responsive, Lighthouse and visual gates. Copilot completed review of this exact head at 2026-10-12T16:41:22Z: approval recommended, zero findings. Local affected suite: 99 passed; full Python suite: 2030 passed, 1 pre-existing skip. Working tree clean.

Coordinator must obtain the actual independent review before merge. Original #831 thread intentionally remains open until this source fix is merged and regenerated artifacts visibly demonstrate deterministic ordering and evidence-relative October wording. No generated checked-in files changed; no video approval performed.

[jmservera]

AI functional approval — Rusty, independent reviewer (not human signoff).

APPROVE exact head 1e8c5bd064d8c1c3f557b3eed4f4a5e9ade8cd55. Reviewed full diff and synthesis/cache/rollup/yearly paths; no blocking findings. Per-week duplicate suppression is preserved; descending-count/lexical ranking stabilizes ties and top-five cutoff. Version 9 invalidates old checksums without changing artifact schema. October transition is evidence-relative.

Independent python3 verification: old full renders produced 5 distinct outputs across 5 seeds; fixed renders produced 1, for both single/multiple weeks. Affected tests: 109 passed, 1 skipped. All 18 hosted checks passed; latest-head Copilot completed, zero unresolved threads; current with main. Merge eligible. Recovery still requires owning regeneration and W42 video completion, not merely green dispatch.