v0.3.1

Fixed

• The documented verification API was unimportable on a plain install.
  lethe/cert_schema.py imports jsonschema at module level, but the
  dependency was declared only under the dev and mcp extras — so
  pip install lethe-delete followed by
  from lethe.cert_schema import verify_certificate_json raised
  ModuleNotFoundError. That is the structured, machine-readable verification
  path (the one returning KEY_ID_MISMATCH / PAYLOAD_TAMPERED), and
  docs/key-rotation.md tells readers to call it. jsonschema is now a base
  dependency: schema-validated verification is not an optional add-on for a
  tool whose claim is that its certificates are independently verifiable.

  The cryptographic path was unaffected — lethe verify and
  lethe.certificate.verify_certificate worked throughout.

Added

• A base-install CI job that installs the package with no extras and
  imports every module a user can reach without opting in, then verifies a
  certificate end to end. It runs from outside the checkout so Python loads the
  installed package rather than the source tree — importing from the tree
  succeeds regardless of what the wheel declares, which is precisely why this
  slipped through. No unit test could have caught it: the dev environment
  always has the extras installed. Confirmed to fail against v0.3.0 and pass
  against this release.