Cardano Updates

Remove duplicate uppercase mapping for TANG token

Delete the duplicate mapping file with uppercase 'E' in the filename:
bf9354cba4ee83c5de05c72830c6430967a26a1656b06293541d23e154414E47.json

The correct lowercase version already exists:
bf9354cba4ee83c5de05c72830c6430967a26a1656b06293541d23e154414e47.json

The uppercase file was added in commit 7026c474 (2023-03-04) and
bypassed the CI hex check because it used [[:xdigit:]] at the time,
which matches both upper and lowercase hex. Both files map to the
same TANG token but the uppercase filename violates README rule #3:
"The file name must match the encoded subject key of the entry, all
lowercase."

Fixes: #7933

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

Enforce README rule #3 ("The file name must match the encoded subject
key of the entry, all lowercase") at the CI level by adding two new
checks to the PR validation pipeline:

1. Subject field inside the JSON must be all lowercase hex [0-9a-f]
2. Subject field must exactly match the filename (without .json)

Previously only the filename was validated for lowercase hex, but the
subject field inside the JSON was never checked. This allowed entries
with uppercase hex in the subject to pass CI. There are currently 40
existing files with uppercase hex that were merged before or while
the filename check was being introduced (see #7933).

Also adds the new fail flags to the rm -f cleanup line to prevent
stale flags from causing false failures.

Refs: #7933

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

Add token metadata for ANKH