chunkshop 0.9.0

Two correctness/perf fixes. The minor bump is for the search-pool default flip
(#64): read pooling is now on by default, so search callers that previously opened
a fresh connection per call now reuse warm connections — a transparent, opt-out
behavioral change worth a version signal. Also fixes symbol_aware silently
dropping symbols for path-less documents (#69). Python-only this release; the Rust
crate is a lockstep version bump with no functional change.

Fixed

• symbol_aware no longer mislabels path-less code as unsupported_language
  (#69). The chunker resolved language only from a file extension in
  doc.metadata.path / source_path or a path-shaped doc.id. Callers passing a
  synthetic id / stele:// URI with no path (e.g. pg-raggraph / bento) got
  fallback_reason="unsupported_language" and zero symbols for ordinary
  sources — ~45% of .py and ~90% of .ts/.tsx files in a real repo. Language
  is now resolved in layers, most- to least-explicit:

  1. a new SymbolAwareChunker.language config override (validated against the
     known language tags),
  2. a doc.metadata['language'] hint (exact tag or an extension alias like
     "tsx" / ".ts" / "py"),
  3. a broadened set of path-like metadata keys (file_path, filename, uri,
     url, rel_path, … in addition to path / source_path),
  4. a path-shaped doc.id (unchanged), then
  5. a conservative content heuristic covering all ten supported languages
     (python, java, go, typescript, javascript, rust, c, cpp, csharp, ruby).

  The content heuristic scores language-distinctive markers and returns a result
  only on a clear, unambiguous winner — prose and near-ties return nothing and
  fall back as before, so symbol_aware_fallback now fires only for genuinely
  unsupported input. A wrong guess can never do worse than the prior
  unknown-language fallback.

Changed

• Read-connection pool is on by default (#64). The opt-in
  CHUNKSHOP_SEARCH_POOL pool — the biggest single search win (hybrid median
  30.8 ms → 10.5 ms, −66%, byte-identical ranking) — now ships on and is
  transparent. Set CHUNKSHOP_SEARCH_POOL=0 (also false/no/off) to restore
  the historical per-call connect. Made safe with three guards:

  • Retry-once on a broken connection. A reused idle connection that turns
    out dead (server restart / idle timeout) is discarded and the query retried
    once on a fresh connection, so a restart self-heals instead of surfacing an
    OperationalError. A fresh connection that fails is a real error and is not
    retried. Validated against real Postgres by terminating a pooled backend.
  • Fork reset. An os.register_at_fork child handler drops inherited
    connections (psycopg sockets do not survive os.fork). The subprocess
    orchestrator spawns via exec and never inherits the pool.
  • Max-idle-age recycle. A connection idle past 300 s is recycled on acquire
    rather than handed out stale.

Added

• SymbolAwareChunker.language — force one language for every document in a
  cell, bypassing per-document detection. Must be a known codeparse language tag;
  rejected at config-load otherwise.