v0.7.2

Release: dispatchable tap job and a clear error when the app token fails

The v0.7.1 tap push failed with "Not Found" from the installation lookup
because the tap GitHub App had been created but never installed on
planesailingio/homebrew-tools. The app is now installed; this makes the
workflow easier to recover and harder to misdiagnose:

- workflow_dispatch with a `version` input runs only the tap job for a
  release that is already published, so a failed tap can be redone without
  re-tagging. build and release are skipped on dispatch.
- A step after the token mint prints, on failure, what the two common
  errors mean (app not installed vs. app id/key mismatch).
- docs/releasing.md: verify the install took, share the org values with
  every tool repo, and list the failure signatures and re-run paths.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>