v0.14.1

Session-end / incremental-compile efficiency (issue #370) plus a self-healing
index backstop (#373). No public API change; opt-in config knobs only.

Upgrade note: session-end --dry-run changed semantics — it is now a
cheap manifest-diff preview (no compile, no cluster/merge, no chromadb, no
embedding-model load), not a whole-corpus compile-check. If you relied on
--dry-run to smoke-test a compile, run session-end --full (or a real
run) instead. See the behavior note below.

Changed — behavior

• session-end --dry-run is now a cheap manifest-diff preview (#370). It no
  longer compiles, clusters, or merges, and never opens chromadb or loads the
  embedding model — it reports intended-work counts (new_or_changed,
  reindex.would_change) from the manifest diff and exits. Previously a dry-run
  paid the full whole-corpus cost.
• Incremental compile is delta-scoped on the client=None path (#370). A
  session-end/ingest now re-clusters and re-merges only the clusters a change
  actually touches (the changed file's prior cluster plus any above-threshold
  neighbors, closed to a fixpoint over cached embeddings); other auto-*.md are
  left untouched. The nightly LLM run stays whole-corpus. Correctness falls back
  to a full compile (logged) when a change can't be cleanly bounded.
• cluster_id is now content-addressed (was a positional sequence index) so
  full and delta runs mint identical ids. One-time effect: the first full run
  after upgrade rewrites every auto-*.md once as ids re-stamp; harmless (recall
  reads all auto-*.md) and self-healing.

Added

• Stat (mtime/size) pre-filter on the index and ingest manifests (#370).
  Unchanged files reuse their stored content hash instead of re-reading and
  re-hashing every wiki file on each build. A page whose validity window expires
  still drops with zero reads (the valid_until bound is recorded in the
  manifest). --full still forces a complete re-hash.
• Self-healing periodic full re-hash backstop (#373). Config
  librarian.reindex.full_rehash_max_age_days (default 7): when the manifest has
  not had a full re-hash in that window, the next incremental reindex re-hashes
  every file (catching a content edit that preserved both mtime and size) while
  still applying only the delta — seconds, not a full re-embed.
• Delta config knobs: librarian.delta.enabled (default true),
  librarian.delta.max_affected_clusters (8), librarian.delta.max_affected_members
  (200) (#370).

Fixed

• fetch_embeddings crashed on chromadb's numpy embeddings array (ambiguous
  truth-value) whenever embeddings were returned, which had effectively broken
  vector-backend clustering; fixed on the read path (#370).