Cardano Updates

Previously the catch-all case silently accepted any version when
succVersion returned Nothing. Now it explicitly fails.

Changes made with the help of an LLM

Test that bytes/text up to 64 bytes decode successfully, and that
values exceeding 64 bytes are rejected.

Changes made with the help of an LLM

The CDDL spec requires `bytes .size (0..64)` and `text .size (0..64)`
for transaction metadatum, but the decoder did not enforce these limits.
This moves the size validation into `decodeMetadatum` so it aligns with
the CDDL spec. The `Arbitrary Metadatum` instance is also constrained
to produce valid values, and the previously disabled CDDL anti-tests
are now enabled.

Changes made with the help of an LLM

Signed-off-by: Francisco Javier Ribo Labrador <[email protected]>

* mithril-stm from '0.9.34' to '0.9.35'

Signed-off-by: Hyperledger Bot <[email protected]>
Co-authored-by: Hyperledger Bot <[email protected]>

They now need some real SNARK proof.

Signed-off-by: Hyperledger Bot <[email protected]>
Co-authored-by: Hyperledger Bot <[email protected]>

- Rewrote the governance model page to use present tense, reflecting that CIP-1694 and decentralized governance are now fully live on mainnet.
- Clarified the tricameral model (Ada Holders/DReps, SPOs, and the elected Constitutional Committee).
- Added a high-level list of the 7 governance action types.
- Moved historical context (SanchoNet, Chang, and Plomin hard forks) into a dedicated "Brief History" section.
- Replaced the outdated SanchoNet call-to-action with links to live mainnet participation tools like GovTool.
- Improved overall readability for general Ada holders.

nix: Revert `lastModified` in `flake.lock`

Signed-off-by: Eric Torreborre <[email protected]>