docs: refresh documentation after the migration

[mkotelnikov]

Documentation refresh. No code, config, lockfile or CHANGELOG changes.

Changes

• Root README rewritten as an operating manual for this repository. The old one described backbone, platform, workspace and AI packages that are not in this repository. It now covers the 15 view packages, the source layout, building and testing (Node 24, pnpm via corepack), how a host app wires the fragments, failure modes with the text users see, commands, and the changesets release flow.
• Package READMEs: each one checked against src/index.ts and its re-exports. Each now has the entry points (., ./fragment, ./styles), peer dependencies, examples using real exports, and failure modes. Stale claims fixed:
  • DirectoryPickerEmptyState is in ui.view.react, and workspace.view.react has no named exports.
  • mime.view.markdown has its own <Markdown> component and no longer uses a chat package.
  • Layout restore reads the LayoutStore adapter, not localStorage.
  • SpecRenderer has a handlers prop.
  • Old package names and pinned versions removed.
• New READMEs for ai-local-models.view.react and webapp.view.react.
• PACKAGE_README.template.md now follows the README section order.
• package.json description fields fixed for the root, explorer.view.react (there is no tree, context menu or search panel) and workspace.view.react (it does not export AppWorkspaceProvider, DirectoryPickerEmptyState or ReconnectBanner).

Found while checking the docs (not changed here)

• .github/workflows/release.yml only runs when the repository is statewalker/statewalker-workbench, so it never runs in this repository. ci.yml is still an inline workflow and does not call the shared one.
• shell.view.react's JsonPanel renders SpecRenderer without handlers, so spec actions in dock tabs do nothing.
• ai-local-models.view.react imports @json-render/react directly instead of going through render.view.react. The registry it puts into json:catalogs has empty handlers.
• workspace.view.react hard-codes the product name "SandClaw" in its header label.
• Several packages declare dependencies they never import, for example workspace.view.react in inline.view.react, settings.view.react and the mime.view.* packages.

🤖 Generated with Claude Code

https://claude.ai/code/session_01DAiZN6XrTAdQpNN3eXEz2U