Prepare Cornerfill 0.0.1

[alowpoly]

Summary

• set the published package version to 0.0.1
• document the fail-closed inset border topology limitation
• narrow the unequal-border support statement to the implemented contour envelope

Verification

• npm test: 57 passed
• runtime browser matrix: 27 passed in each of Chrome, WebKit, and Firefox
• packed tarball installed in a clean consumer and all four exports imported
• exact-source Firefox Mario crop proof completed through moz-element with clean teardown

The full local 20-case oracle retry encountered Playwright CLI screenshot/navigation timeouts. Candidate tolerances and the 30-second driver safety limit were not changed.