feat: scaffold package scripts on init

[miguel-heygen]

Problem

New HyperFrames projects should feel like normal JavaScript projects immediately after hyperframes init: users should have a canonical npm run dev, npm run check, npm run render, and npm run publish loop without needing to memorize raw CLI commands.

At the same time, the scaffold should stay opinionated. Adding many aliases would make the project surface harder to explain and maintain.

What this fixes

• Writes a default package.json during hyperframes init when the selected example does not already provide one.
• Adds four project scripts only:
  • dev -> preview in Studio
  • check -> lint, validate, and inspect in sequence
  • render -> render the video
  • publish -> publish the project
• Pins generated scripts to the CLI version that created the project in packaged builds, while keeping source-checkout tests on the unpinned dev fallback.
• Uses npx --yes inside scripts so first-run commands do not stop on an install confirmation prompt.
• Updates generated AGENTS.md and CLAUDE.md guidance to present the same four-command workflow.
• Updates the non-interactive init success message to include npm run dev, npm run check, and npm run render.

Root cause

scaffoldProject() copied the example, wrote meta.json and hyperframes.json, then copied agent guidance files. It never created a package manifest, so generated projects had no project-local command contract even though the workflow has stable repeated commands.

This revision keeps the scaffold narrow: package.json is the project workflow contract, but direct CLI usage remains available for advanced or one-off commands.

Verification

Local checks

• TDD red check from the first pass: bun run --filter @hyperframes/cli test src/commands/init.test.ts failed after updating the expected generated UX because npm run check was not emitted yet.
• bun run --filter @hyperframes/cli test src/commands/init.test.ts
• bunx oxlint packages/cli/src/commands/init.ts packages/cli/src/commands/init.test.ts
• bunx oxfmt --check packages/cli/src/commands/init.ts packages/cli/src/commands/init.test.ts packages/cli/src/templates/_shared/AGENTS.md packages/cli/src/templates/_shared/CLAUDE.md
• bun run --filter @hyperframes/cli typecheck
• bun run --filter @hyperframes/cli test
• bun run --filter @hyperframes/cli build
• bun run --filter @hyperframes/studio build
• git diff --check
• node packages/cli/dist/cli.js --version

Generated-project smoke at /tmp/hf-init-package-scripts-opinionated:

• node packages/cli/dist/cli.js init /tmp/hf-init-package-scripts-opinionated --example blank --non-interactive --skip-skills
• inspected generated package.json and confirmed exactly dev, check, render, and publish
• confirmed packaged scripts use npx --yes hyperframes@0.4.39 ...
• npm run check
• npm run render -- --quality draft --workers 1 --fps 24 --output /tmp/hf-init-package-scripts-opinionated.mp4
• ffprobe -v error -select_streams v:0 -show_entries stream=width,height,avg_frame_rate,duration -show_entries format=duration,size -of json /tmp/hf-init-package-scripts-opinionated.mp4
• npm run publish -- --help

Browser verification

• Started the generated project through the new script: npm run dev -- --port 5199.
• Used agent-browser to open http://localhost:5199/#project/hf-init-package-scripts-opinionated.
• Verified the Studio project loaded with the expected project name, controls, timeline, and composition player frame.
• Captured screenshot: /tmp/hf-init-package-scripts-opinionated-browser.png.
• Captured agent-browser-driven recording: /tmp/hf-init-package-scripts-opinionated-browser.webm.
• Verified recording metadata with ffprobe: 14.4s, 61 KB.

Notes

• The generated source-checkout test still expects unpinned npx --yes hyperframes ... because source mode reports 0.0.0-dev; the packaged CLI smoke covers the real-user pinned path.
• npm run publish was verified with --help only to avoid creating a real publish side effect during PR validation.