v0.1.1

Release-pipeline fixes. The v0.1.0 tag was created but never produced
published artifacts (PyPI, npm, GHCR) because of a sequence of CI
configuration failures; v0.1.1 is the first version where the release
workflow runs end-to-end. The behavior of the code itself is unchanged
from what v0.1.0 was supposed to ship — see the [0.1.0] section below
for the feature list.

Release-pipeline fixes since v0.1.0

• Container builder switched from alpine/musl to debian/glibc;
  sqlite-vec.c uses BSD type names that musl doesn't provide.
• Cross-compile matrix now uses CGO_ENABLED=1 with per-target
  toolchains (gcc on linux/amd64, gcc-aarch64-linux-gnu on
  linux/arm64, mingw on windows/amd64, native clang on darwin/arm64).
• Windows binary build moved to a windows-latest runner with a
  workflow step that fetches sqlite3.h from the SQLite amalgamation.
• npm package gains repository / homepage / bugs / keywords
  fields so npm provenance verification accepts the publish.
• Postgres schema gained the signature column that the store
  queries already referenced.
• MinIO service swapped from the now-vanished bitnami tag to the
  official minio/minio image, with bucket creation via mc mb in
  a workflow step.
• A flaky scheduler test that raced with t.TempDir cleanup now
  waits for the goroutine to finish on cancel.