v0.12.2 — daemon fd-exhaustion + recency-aware ask

Two bug fixes (drop-in over v0.12.x):

tesserae engine fd exhaustion. A long-running daemon (especially fleet mode) could spiral into Too many open files / unable to open database file storms — the session tailer opened every known transcript's .jsonl (+ a sqlite connection) on every tick. A cheap stat() now skips idle transcripts, vanished files are pruned, and a truncated file is re-read from the start. Steady-state ≈ 0 opens for the idle majority. Recommended if you run tesserae engine across many projects.

Recency-aware ask. Federated ask blended pure semantic relevance, so a 'what's recent' query magneted onto old 'Review ALL improvements' syntheses. It now blends in a recency score anchored on a node's session timestamps (started_at/ended_at), a leading date in its title, else neutral — relevance still dominates (0.25 default), tunable via ask --recency-weight (0 = pure relevance). Compiled/export artifacts stay byte-deterministic.

Full notes: https://github.com/ca1773130n/Tesserae/blob/main/docs/release-notes/v0.12.2.md