v0.2.16

Changed

• Engine floor moves to kglite 0.16.22, spanning two upstream releases.
  codingest never took 0.16.21, so 0.16.21 and 0.16.22 land together. Both are
  additive for the builder — every .kgl persistence entry codingest calls is
  byte-identical and the golden digests prove it — and neither breaks anything
  this repo compiles: the blueprint spec structs (Blueprint, Settings,
  NodeSpec, FkEdge, JunctionEdge) gained fields and
  JunctionEdge::target became Vec<String>, but codingest constructs no
  blueprint and calls neither from_blueprint nor from_records, so the
  struct-literal break and the now-honoured on_missing_endpoint spec key are
  both unreachable here. ServerExtensions gained read_only(); codingest
  composes its extensions through
  ServerExtensions::default().with_workspace_graph(...), a builder chain, so
  the added field is not a literal break either — and codingest does not pin
  its servers read-only, because an operator running codingest-mcp --writable
  is asking for exactly that.
• codingest-mcp now refuses to boot on a skills: pack a manifest declares
  but that does not exist. One bad path used to fail the whole skill-registry
  build and boot the server anyway with every skill gone — the bundled
  methodology included — while the graph tools answered normally and
  --selftest printed PASSED. The boot error names what was written and where
  it resolved to, and --selftest now prints the number of skills the session
  serves, so an opted-in deployment that resolved nothing is visible. codingest
  ships no manifest and declares no skills pack, so no server started from this
  repo's own commands can hit it; an operator manifest pointing at
  codingest-mcp can.
• save_graph(force: true) now requires the write opt-in. It is offered
  only where mutations are (--writable / extensions.writable: true) and
  refused on a server that registers save_graph alone via
  builtins.save_graph: true, because a forced re-encode moves the file's
  identity and makes every peer serving it pay a full re-read. A plain
  save_graph from such a server still publishes unsaved changes. Also: a save
  that persisted only boot configuration says so instead of reporting a node
  count nothing moved, and a refused save on a clean server says "Nothing was
  changed here" rather than claiming unsaved changes are still queryable.
  docs/mcp.md states the force restriction.
• A fired query deadline now raises CypherTimeoutError, not
  CypherExecutionError. codingest query --timeout and any MCP
  cypher_query deadline surface kglite's error, so a caller catching
  kglite.CypherExecutionError specifically for a timeout must add
  CypherTimeoutError; kglite.CypherError catches both, unchanged. Nothing
  in codingest names a KgError variant, so no source here moved.
• Also in the floor and unreachable from this repo: relationship alternation
  [:A|B] now works inside EXISTS { } / count { } / size(...) (the
  shipped code-review queries use no alternation, so nothing was working around
  it); ranked retrieval (text_bm25, vector_score) on a property with no
  index raises instead of answering zero rows; ontology_audit() gained a
  property column, edge_property_violation() a properties column, and a
  blueprint gained "list" columns, node-spec labels, FK-edge properties and
  union-target junction edges — codingest declares no ontology, builds no
  blueprint, and pins no yielded column set.
• Floor declarations moved together: pyproject.toml
  (kglite>=0.16.22,<0.17) and its lockstep comment, the workspace kglite /
  kglite-mcp-server pins, ci.yml's pinned wheel install, the codingest-py
  import-failure hint, crates/codingest/Cargo.toml, and the README/docs
  install snippets. The per-feature kglite ≥ 0.16.19 / 0.16.20 qualifiers
  in docs/mcp.md are dropped rather than renumbered — the floor already
  guarantees them, so they were maintenance with no reader. Historical
  citations are deliberately unchanged: PARITY.md's per-release records, the
  benchmark baseline captures, docs/index.md's "Beneath it, 0.16.x" chain,
  and the kglite 0.16.19 attribution on the accessor code_tree_cli.rs
  adopted then.