[Kinflou]

Stacked on #41.

Each language page's Runtime section is now rendered from runtime conformance. Before, it was a placeholder.

• scripts/sync-language-support.py also reads:
  • the wire corpus's features.json (Runtime wire conformance: vectors, Rust support and report runtime#13);
  • each runtime's report: Rust's runtime/conformance/reports/rust.json, and TypeScript's runtime/conformance-report.json (comline-typescript#50).
• From those it renders:
  • a Runtime table per language page (state, note, tracking link, the cases still failing, and the number of proving cases linked to the vectors);
  • a runtime matrix on the overview.
• New flags read local files instead of fetching: --runtime-features and --runtime-report NAME=FILE. --runtime-rev picks the revision to fetch (default main).
• The overview explains what the runtime states mean and how a runtime claim is proven.
• The Rust and TypeScript framing pages' "Shipped combinations" tables link to the reference page.
• The design contract's wire section names the vectors as the normative examples.

Checked:

• zensical build --strict passes.
• --check passes against local reports.
• The CLI drift check passes.

The drift check fetches the reports from main, so it fails until runtime#13 and comline-typescript#50 merge.