feat(hindsight): add recall_min_scores relevance floor to recall path

[eulahwu917]

Summary

Add opt-in recall_min_scores config key that passes a relevance floor through to Hindsight's recall calls, fixing the "no relevance floor, backfills to token budget regardless of fit" bug that injects stale/irrelevant facts into every turn.

Per Planner spec review (t_babb0d63, APPROVED WITH CORRECTIONS).

Changes

Version pin (B1 — atomic across 3 files)

• plugins/memory/hindsight/__init__.py: _MIN_CLIENT_VERSION 0.6.1 → 0.8.5
• tools/lazy_deps.py: hindsight-client==0.6.1 → ==0.8.5 (exact pin)
• plugin.yaml: hindsight-client>=0.6.1 → >=0.8.5

New config + validation (B2)

• recall_min_scores in get_config_schema() — opt-in dict e.g. {"reranker": 0.01}
• _normalize_min_scores() helper with key whitelist {semantic, keyword, reranker, final}, float coercion, fail-open on invalid input
• Wired in initialize() next to other recall controls

Call-site wiring (2 sites)

• queue_prefetch() — prefetch recall: passes min_scores to arecall(**recall_kwargs)
• hindsight_recall tool — passes min_scores to arecall(**recall_kwargs)
• Reflect call sites intentionally untouched (server 0.8.4 ReflectRequest has no min_scores field)
• No numeric default — ship unset/opt-in only

Tests (16 new)

• _normalize_min_scores validation: None, valid dict, all keys, unknown key dropped, non-numeric dropped, all-invalid returns None, type error, not-a-dict, int→float coercion
• Wiring: prefetch passes/omits min_scores, hindsight_recall tool passes/omits min_scores, malformed config drops with warning and does NOT pass to arecall (fail-open confirmed)

Verification

All 132 tests pass (116 existing + 16 new):

pytest tests/plugins/memory/test_hindsight_provider.py -v
# ============================= 132 passed in 3.15s ==============================

Files changed

• plugins/memory/hindsight/__init__.py (+61 lines)
• plugins/memory/hindsight/plugin.yaml (+1/-1)
• tools/lazy_deps.py (+1/-1)
• tests/plugins/memory/test_hindsight_provider.py (+120 lines)

[alt-glitch]

This was generated by AI during triage.

Related to #64914: both wire Hindsight min_scores into the same recall paths, but this PR changes the dependency floor and config contract. Please choose or consolidate the intended configuration/compatibility policy.