v0.3.0

Two surfaces for the validated generator: an editor integration and a public, comparable
scoreboard. Both build on the existing engine — generation and the static lint gate are unchanged,
and the base install stays GMAT-free.

Added

• VS Code extension — generation commands inside the editor, driving the engine through a thin
  stdio JSON-RPC worker launched in your own Python environment. A draft is shown as a reviewable
  diff and applied only on accept (never auto-applied); lint and dry-run findings surface as inline
  diagnostics, and the provider/model is chosen explicitly from a reachable-providers quick-pick.
  Every .script language feature (highlighting, hover, formatting) stays with the gmat-script
  extension, which it depends on. Published to the VS Code Marketplace and Open VSX in lockstep with
  the package (#72, #73).
• Per-model leaderboard — a harness that scores each seeded provider:model over the evaluation
  suite and writes a ranked leaderboard.json. It ranks on a never-committed held-out set as the
  headline, with the committed public set alongside as the offline-reproducible anchor, so a model
  that overfits the public prompts gains no rank; the board carries aggregates only, and a verify
  step is the firewall that keeps held-out golds off it. Hosted as a static Hugging Face Space — the
  project's one hosted artifact — rebuilt by a gated CI job and a refresh workflow (#74, #75).