release: 0.4.3

release: cut 0.4.0 and publish mfs-server to PyPI (#121)

Move off the beta line: bump mfs-cli, mfs-server, mfs-server-rs, and both
SDKs to 0.4.0 (lockfiles and doc references included), so a single v0.4.0
tag releases everything in lockstep.

Make mfs-server publishable to PyPI:
- give the package its own README (the monorepo root README lives outside the
  project dir, which broke the sdist build) and point readme at it
- add publish-pypi.yml: Trusted Publishing (OIDC), tag-triggered, version-
  guarded, mirroring publish-crates.yml

Document the optional native acceleration instead of shipping it on PyPI:
- Dockerfile gains an ACCEL build-arg that compiles mfs-server-rs in a separate
  stage; the default stays pure-Python and never pulls a Rust toolchain
- deployment.md explains both the Docker and source/maturin paths

Also fix .dockerignore: slashless patterns only match the context root, so
nested target/, .venv/, node_modules/ were never excluded; use **/ prefixes.

Release v0.4.0-beta.2

Patch release on top of v0.4.0-beta.1 with three follow-up fixes.

Wizard (mfs-server setup, mfs-server connector add):
  - rich + questionary UX overhaul: coloured Panel section headers,
    arrow-key selects with per-option trade-off hints, password()
    inputs for secrets, integer validators that re-prompt instead
    of tracebacks
  - probe the live embedding provider for the real dimension
    instead of a hand-curated table that drifted with new models
  - auto-generated auth tokens never echoed on stdout (read from
    server.token file, mode 0600)
  - custom auth token input uses password() so the secret stays
    hidden as the user types
  - fixes 5 validation bugs surfaced by the matrix test pass:
    required-field empty rejection, integer parse errors, Milvus
    Lite path mis-defaulted as remote URI, empty milvus subtable
    in toml, auth mode 3-way select

Server bug fixes:
  - re-load existing Milvus collection on server restart
    (Milvus Lite leaves collections in 'released' state after a
    new client attaches to an existing .db; search would fail
    with code=101 until a server-side reload)
  - discover $MFS_HOME/server.toml in config lookup chain
    (closes the gap where 'mfs-server setup' under a non-default
    MFS_HOME wrote a config that 'mfs-server run' could not find)

Storage refactor (split out from beta.1 cleanup):
  - metadata + transformation_cache ABCs with SQLite/Postgres
    subclasses, single make_*_store factory per kind

Full changelog: v0.4.0-beta.1...v0.4.0-beta.2

v0.4.0-beta.1 — first public beta

Prepare PyPI release workflow

Set up the mfs-cli distribution package, CI checks, release publishing, and install documentation.