refactor(help): shim manifest/staleness/freshness; add rag adapter

[silversurfer562]

Summary

Phase B2 of the architecture-realignment spec. The authoring modules manifest.py, staleness.py, freshness/ moved to attune-author in PR #14 (B1). This PR collapses the help-side originals into thin re-export shims that emit DeprecationWarning and adds the rag-adapter that pairs with attune-rag PR #10 (Phase A).

• Replace attune_help/manifest.py, staleness.py, freshness/__init__.py, freshness/symbols.py with shims (from attune_author.X import * + DeprecationWarning).
• Stop re-exporting manifest/staleness symbols from attune_help.__init__ so a plain import attune_help is warning-free during the deprecation window. Engine-related re-exports preserved.
• Add attune_help/adapters/rag.py::AttuneHelpAdapter — a frozen dataclass that satisfies attune-rag's HelpCorpusAdapter protocol (templates_root, version).
• Bump attune-help to 0.11.0 and declare attune-author>=0.7.0 as a transitional dep (see Coordination notes below).
• 4 new shim tests (tests/test_authoring_shims.py) verify symbol identity through the shim AND the DeprecationWarning fires per module.

Net diff: +300 / −1090 (~790-line shrink in attune_help).

Closes / does not close

• Closes finding docs(rag): 0.7.0 spec — path-keyed sidecars + Shape 2 validation #1 (ADR-002: authoring code in attune-help) — the actual code now lives in attune-author; the shims keep imports working for one minor release.
• Does NOT close finding feat: v0.7.0 — RAG-ready fixtures + polished path-keyed summaries #3 (ADR-001 leak in discovery.py) — see "Course-correction" below.

Course-correction: B2.3 deferred

design.md describes attune_help/discovery.py as duplicating retrieval scoring that ADR-001 reserves for attune-rag, and proposes routing through attune_rag.KeywordRetriever. After reading the actual code, I think this misidentifies what discovery.py is doing:

• discovery.search() does typo-tolerant fuzzy slug match via difflib.SequenceMatcher plus a substring bonus — its job is autocomplete / "did you mean X?".
• attune_rag.KeywordRetriever does token-overlap content scoring weighted across path / summary / content / aliases / related — its job is RAG retrieval.

tests/test_discovery.py::test_search_finds_misspelling asserts that search("secrity-audit") finds security-audit. KeywordRetriever doesn't (and shouldn't) do character-level fuzz; it would tokenize both inputs and find no overlap. Replacing discovery's loop with KeywordRetriever().retrieve(...) would be a behavior break, not a duplication removal.

Recommendation: leave discovery.py as-is in this PR. If finding #3 still feels like the right call, scope a follow-up that either (a) adopts KeywordRetriever as a second mode for content-based search while keeping fuzzy slug autocomplete, or (b) revises the finding now that the code is closer to scope. Happy to course-correct if you'd rather close it now.

Coordination required before merge

1. attune-author release. This PR declares attune-author>=0.7.0, but the latest published is 0.6.2 — without the relocated manifest/staleness/freshness modules. Need a 0.7.0 (or 0.6.3) release of attune-author that ships the B1 changes BEFORE this PR is published to PyPI. Local dev install (pip install -e ../attune-author) works against main.
2. attune-author has a stale attune-help>=0.10.0 dep in pyproject.toml that's a leftover from the pre-B1 era (no from attune_help imports in attune-author/src anymore). Worth a separate one-line cleanup PR on attune-author so we don't have a circular package-metadata edge.
3. tech.md tension. ADR constraint: "attune-help install footprint: zero required deps beyond python-frontmatter." This PR adds attune-author>=0.7.0 as a transitional required dep. Carried forward in CHANGELOG; constraint restored when shims are removed (target 2026-07-07, tracked by RemoteTrigger 01Vuq4AiaKLspV2wNVpCQN1o).

Test plan

• Full attune-help suite green: 265 passed, 3 expected DeprecationWarnings (existing test_manifest/test_staleness/test_symbols intentionally exercise the shims).
• New tests/test_authoring_shims.py — 7 tests: 4 parametrized DeprecationWarning checks + 3 symbol-identity checks (Feature is attune_author.manifest.Feature, etc).
• ruff check src/ tests/ clean.
• Pending coordination: cut attune-author 0.7.0 (or pin git ref) so installing pip install attune-help==0.11.0 resolves cleanly.

🤖 Generated with Claude Code

[silversurfer562]

attune-author 0.7.0 just published — CI dep resolution should now succeed. Re-running checks.