feat(sleep): group mined tasks by skill hint with catch-all fallback

[bogdanbaciu21]

Summary

Third review-sized slice of #120: the grouping primitive, so mined tasks can be
routed per skill while everything without clear evidence stays in the existing
managed-skill catch-all.

Adds mine.group_tasks_by_skill_hint(tasks, managed_skill_name), a
deterministic, side-effect-free helper returning ordinary insertion-ordered
dicts/lists:

• groups preserve first-seen order, and so does task order inside a group;
• each task ID is emitted exactly once, reusing dedup_tasks merge semantics
  (source sessions unioned, best outcome kept);
• a task reaches a hinted group only when every observation of that ID agrees
  on the same non-empty hint;
• absent/blank hints, two different hints for one ID, and a mixture of hinted and
  unhinted observations for one ID all route to managed_skill_name;
• a hint equal to managed_skill_name lands in that one group, never a duplicate.

The grouping rule is deliberately the same order-independent "full set of
non-empty hints" rule you asked for in the #183 review, so grouping and
dedup_tasks cannot disagree about what an ambiguous ID means.

Nothing else changes: mine(), filter_tasks_for_target(), cycle, gates,
staging, and adoption are untouched, and the caller supplies the configured
managed-skill name rather than the helper resolving paths or reading skill files.

Rebased onto current main (e7014cd); the earlier stacked parents (#182, #183)
have landed, so this is now a single commit against main.

Tests

Base is unmodified main at e7014cd, same machine, same interpreter
(CPython 3.12.13, macOS):

Run	Result
pytest tests/test_sleep_engine.py (this branch)	94 passed, 1 skipped
pytest tests (this branch)	611 passed, 6 skipped, 130 subtests, 2 failed
pytest tests (base main @ e7014cd)	603 passed, 6 skipped, 130 subtests, 2 failed
ruff check .	identical finding set to base - 0 new

The 2 failures are tests/test_superpowers_scenarios.py::TestOverlayIntegration
(test_skill_copied_to_correct_path, test_source_checkout_unchanged). They are
the macOS /var → /private/var symlink artifact and reproduce unchanged on
untouched main, so they are not regressions from this branch.

Covered by the new tests: empty input, legacy hint-less tasks, blank hint,
interleaved alpha/beta/alpha ordering, duplicate ID merge, conflicting
hints, partial hint evidence, and a hint equal to the managed skill name.

Refs #120

[Copilot]

Pull request overview

This PR adds the remaining “grouping primitive” needed to route mined sleep-engine tasks per skill, using harvested Skill tool invocations as evidence, while keeping ambiguous or hint-less tasks in the existing managed-skill catch-all.

Changes:

• Add SessionDigest.skills_used harvesting from Claude Skill tool-use blocks and propagate a derived TaskRecord.skill_hint into both heuristic and LLM miners.
• Introduce mine.group_tasks_by_skill_hint(tasks, managed_skill_name) to deterministically group (and deduplicate) tasks by unambiguous skill hint, with a managed-skill fallback.
• Add focused unit tests covering harvesting, hint propagation, dedup semantics, and grouping behavior.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tests/test_sleep_skill_hint.py	Adds unit tests for skill_hint propagation, serialization, and dedup behavior.
tests/test_sleep_skill_harvest.py	Adds unit tests for harvesting Claude Skill tool invocations into skills_used.
tests/test_sleep_engine.py	Adds coverage for group_tasks_by_skill_hint behavior and ordering guarantees.
skillopt_sleep/types.py	Extends core dataclasses with SessionDigest.skills_used and TaskRecord.skill_hint.
skillopt_sleep/mine.py	Adds session_skill_hint, propagates hints in heuristic mining, extends dedup_tasks, and introduces group_tasks_by_skill_hint.
skillopt_sleep/llm_miner.py	Propagates session-derived skill_hint into LLM-mined tasks.
skillopt_sleep/harvest.py	Extracts Skill targets from tool-use blocks and persists them into digests.

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[bogdanbaciu21]

Thanks for the welcome on #120. To keep review load bounded and follow the incremental shape Yif-Yang suggested, I'm closing this PR for now and will reopen it once #182 (the harvesting slice) lands or the maintainer asks for the next slice. The branch stays on my fork so this can be re-opened as-is. Happy to restructure if a different cadence is preferred.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

Suppressed comments (1)

skillopt_sleep/mine.py:262

• group_tasks_by_skill_hint currently returns TaskRecords whose skill_hint can disagree with the grouping decision (e.g., blank/whitespace hints remain truthy, and mixed hinted+unhinted observations still dedup to a non-empty skill_hint). It also mutates the original input TaskRecord objects via dedup_tasks, which conflicts with the PR’s stated “side-effect-free” intent. Consider normalizing hints (strip, treat blanks as empty), deduping on copies, and then forcing task.skill_hint to the resolved hint actually used for grouping so consumers can’t observe an inconsistent hint.

    observed: dict = {}
    for t in tasks:
        observed.setdefault(t.id, set()).add((t.skill_hint or "").strip())

    groups: Dict[str, List[TaskRecord]] = {}