fix(docs): prevent stale installation guidance in beta packages

[titan-ron]

Change

The published 0.1.0-beta.1 archive still tells application users to install a maintainer-supplied tarball, although the source README now documents npm installation. Check the README inside every tested archive against the checkout, require the public npm beta install command, and reject archive-only installation guidance and unpublished claims. Start the Doppler guide with the installed CLI and link to contributor setup.

The existing release planner selects 0.1.0-beta.2, including the corrected README and fixes already on beta. Keep the root manifest private and let CI assign the release version. After this PR is approved and merged, manually dispatch the existing ci.yml workflow on beta with publish=true to stage the tested archive through OIDC. npm maintainer approval remains the publication gate; do not create release tags before publication is verified.

Validation

• Pinned Node.js 24.19.0: lint, strict types, build, 101 unit/tooling tests, coverage gate and 41 process tests passed.
• Packed package: 16 runtime checks and two typed consumers passed.
• The actual published beta archive fails the new README check. Using its obsolete README in both source and build also fails the installation check.
• Generated a non-publishing 0.1.0-beta.2 release plan, built its final archive, recorded integrity and passed its package checks.
• Hosted CI passed the build, coverage upload and all consumer jobs (Linux Node 20/22/24 and macOS Node 24), including the isolated Linux keyring check. Static analysis passed.
• Downloaded that exact hosted 0.1.0-beta.2 archive, verified its recorded integrity, confirmed its README matches the corrected source, and independently passed all 16 runtime checks and both typed consumers.
• Release audit passed: zero runtime findings and the unchanged 12 bounded development exceptions.
• Live read-back confirmed RELEASE_ENABLED=true and the release environment accepts only beta, with no required GitHub reviewers.
• npm stage listing currently returns E401 in the maintainer session; confirm no pending candidate before staging. No local npm login or publication was attempted.

[github-code-quality]

Code Coverage Overview

Languages: TypeScript

TypeScript / code-coverage/vitest

The overall line coverage in commit a30356a in the titan/check-package-... branch remains at 95%, unchanged from commit bfe3814 in the beta branch.