Cardano Updates

Upstream now includes the prettyprinter switch (PR #428) and briefHangPoint
formatter (PR #425), making the fork unnecessary.

Two capabilities from the fork are not available in upstream:
- prefRenderHelp: no hook to inject a custom renderer into the --help path
- helpEmbedBriefDesc: replaced with the coarser briefHangPoint 35

The CLI_HELP_TRACE tracing (Ann/AnnTrace) is removed; it was never wired up.
Golden tests will need updating due to formatting changes.

Signed-off-by: Jonathan Lim <[email protected]>

Adds AsData.Spec to frontend-plugin-tests: a module compiled with
-fplugin PlinthPlugin that derives 'AsData via PlinthPlugin' and uses the
generated Circle/Rectangle pattern synonyms. If the plugin does not fire, the
deriving clause survives to the renamer and the module fails to compile, so
compilation itself proves the plugin works; the HUnit case additionally
exercises the generated synonyms at runtime.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

Remove era prefix from rule names

The golden test compares 'cardano-crypto-leios/test/golden/LeiosCert'
byte-for-byte against the hex-dump output of 'encodeWithIndex'. Without
this attribute, the default Windows 'core.autocrlf=true' translates LF
to CRLF on checkout and the comparison fails, even though the file is
committed with LF endings.