Template README + template.json generation tool

[bradleyshep]

Description of Changes

Adds tools/templates/ scripts to derive template metadata from manifests and generate READMEs from quickstart docs. Replaces slug-based builtWith with manifest-derived data and hardcoded quickstart mappings with discovery from docs.

Manifest-based builtWith (update-template-jsons.ts)

• Reads package.json, Cargo.toml, and .csproj to populate builtWith in .template.json.
• Scoped npm packages normalize to scope (@angular/core → angular). Excludes @types/*. Adds nodejs only for nodejs-ts when @types/node is present.
• Root manifests processed before subdirs; primary framework first (e.g. react before spacetimedb in react-ts). Dependencies reordered in package.json where needed.

Dynamic quickstart discovery (generate-template-readmes.ts)

• Discovers template → quickstart by parsing --template X from files in docs/docs/00100-intro/00200-quickstarts/.
• Optional quickstart override in .template.json; must resolve under quickstarts dir.
• chat-react-ts has no quickstart; uses manual README.

New: tools/templates/ (update-template-jsons.ts, generate-template-readmes.ts, README, package.json, pnpm-lock). Modified: all templates/*/.template.json (added builtWith), new/generated templates/*/README.md.

API and ABI breaking changes

None.

Expected complexity level and risk

1 – Dev tooling only. No runtime or API changes. Scripts are isolated; failures only affect generated metadata and READMEs.

Testing

• cd tools/templates && pnpm run generate completes without errors
• Spot-check builtWith and generated READMEs for a few templates