compute_stale: strict > boundary, threshold=0 disables, future
timestamps treated as fresh (clock skew safety). App::search
re-stamps on cache hit so config threshold changes take effect
without flushing the cache.
Also unblocks the workspace build by plugging placeholder
indexed_at/stale into the two AnswerCitation construction
sites in kebab-rag/pipeline.rs (the score-gate refusal path
forwards from SearchHit; the LLM-citation path uses
UNIX_EPOCH/false until Task 7 wires the real values through
pack_context).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
dfef65f196