feat: add Blume documentation site

[thebuilder]

Summary

• Move the publishable library into packages/react-intersection-observer and Storybook into apps/storybook under a pnpm/Turborepo workspace.
• Replace the user-facing Storybook documentation with a Blume documentation site, including interactive API and recipe demos.
• Add GitHub Release-backed changelog pages, while keeping release notes out of the primary documentation search index.
• Update package publishing, compatibility tooling, CI, and contributor guidance for the workspace layout.

Why

Library consumers need focused product documentation rather than internal Storybook examples. The workspace layout keeps the published package, Storybook, and docs application independently runnable while preserving the root README for GitHub and published-package use.

Validation

• corepack pnpm lint
• corepack pnpm --filter react-intersection-observer test --run (96 tests)
• corepack pnpm --filter storybook typecheck
• ASTRO_TELEMETRY_DISABLED=1 node_modules/.bin/blume build --isolated in apps/docs
• ASTRO_TELEMETRY_DISABLED=1 node_modules/.bin/blume validate --isolated in apps/docs

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Project	Deployment	Actions	Updated (UTC)
react-intersection-observer	Ready	Preview, Comment	Jul 29, 2026 5:41pm

[pkg-pr-new]

npm i https://pkg.pr.new/react-intersection-observer@770

commit: 6b6dcf0