v1.3.1 — Fix broken css2 embed URLs

Fixed

• Broken Google Fonts embed URLs (#1): generate_embed emitted comma-separated
  weights (wght@400,700), which the css2 API rejects with HTTP 400. New
  normalize_weights() converts legacy commas to semicolons, dedupes and sorts
  discrete weights, and passes through .. ranges and explicit axis specs
  (ital,wght@0,400;1,700). Covers the MCP server, CLI scripts, and showcase.
  Thanks @tamasys for the report and PR.
• Showcase generator corrupted correct CSV data into comma/dash URL syntax; static
  fonts now use discrete weights from the Styles column (ranges 400 on static
  fonts), variable fonts use .. ranges. All 100 gallery pages regenerated —
  every embed URL now returns HTTP 200.
• Pairings "Premium Sans" and "Startup Bold" referenced Fontshare fonts not on
  Google Fonts; replaced with the Google alternatives their notes named
  (Plus Jakarta Sans + DM Sans, Outfit + Rubik).
• Startup banner fallback reported stale v1.1.0; version and counts now derive
  from the package.

Changed

• scripts/core.py is now a thin shim over google_fonts_mcp.core — one
  implementation instead of two drifting copies (parity-tested).
• Banner extracted to _banner.py; server.py is tools-only.
• MCP tool and CLI weight defaults use css2 syntax (400;700).
• SKILL.md: MCP-tools note, full fonts.csv schema, lookup/scale modes, css2 rule.

Added

• LICENSE file (MIT was declared but missing; now shipped in wheel + sdist).
• Test suite grown 4 → 27: css2 grammar regression, weight normalization, exact
  scale math, CSV schema, version sync, scripts↔package parity.
• pytest declared as dev dependency; CI runs tests before publishing.
• fastmcp capped <4.