chore(polish): migrate model alias to claude-sonnet-4-6 (deadline 2026-06-15)

[silversurfer562]

Summary

Migrates attune-author's pinned polish model from the deprecated dated alias claude-sonnet-4-20250514 (EOL 2026-06-15) to the family alias claude-sonnet-4-6. Aligns with attune-rag's existing ClaudeProvider.DEFAULT_MODEL pin and Anthropic's recommended migration path.

Top 3 #1 from the 2026-05-08 Monday briefing. Hard deadline 2026-06-15.

Spec: specs/polish-model-migration/{requirements,design,tasks}.md (in the workspace).

Audit findings

grep -RIn "claude-sonnet-4-20250514" across the workspace surfaced two production hard-coded pins (vs the one anticipated in requirements):

File	Role
src/attune_author/polish.py:54 (_POLISH_MODEL)	Drives every polish call (synchronous + batch path).
src/attune_author/doc_gen/config.py:27 (DocGenConfig.model)	Default model for attune-author docs subcommand.

Plus 3 test fixtures in 3 files (test_cli_batch.py, test_maintenance_batch.py, test_polish_improvements.py).

Out of scope (left as historical artifacts): attune-rag/scripts/probe_v2_cache_control.py references the old alias verbatim — V2/V3 verification record.

What landed

• Two production constants bumped (polish.py + config.py).
• Three test fixtures bumped to match.
• New tests/test_polish_smoke.py (5 tests) — pins the wire-level model name across both code paths via mocked SDK calls. Catches the next deprecation immediately at CI time. No API spend.
• CHANGELOG [0.11.1] — documents the rename, the cold-cache caveat, and the optional attune-author cache clear for users who want immediate disk reclaim.
• Version bump 0.11.0 → 0.11.1 (patch — model rename, not API change).

Verification (live, ~$0.04 total)

Check	Result
Synchronous regen (10 features, 30 polish calls)	All 200 OK. New templates landed with coherent content.
Batch submit + resume (1 stale feature, 3 templates)	msgbatch_01JtqmPQMyTfEsHCwceKuGVY ended cleanly: 3/3 succeeded. Templates spliced correctly.
Cache invalidation	Cache went 23 → 53 entries — 30 new under new SHA-key namespace, 23 old remain for TTL prune. Exactly per design.
Full test suite	675 passed, 32 skipped (live + skill-export integration).
Ruff	Clean on all touched files.

Cache-key behavior

_POLISH_MODEL participates in the polish cache key, so this bump cleanly invalidates old entries (they remain on disk until the existing 30-day TTL prune reaps them). No manual nuke needed for correctness; users wanting immediate disk reclaim can run attune-author cache clear.

Test plan

• CI green on all matrix rows (Linux/macOS/Windows × Python 3.10–3.13)

🤖 Generated with Claude Code