Cardano Updates

The upstream library removed cardano-api dependency (PRs #32, #33).
Breaking changes: CardanoApiEra type family removed, Babbage demoted
from RecentEra to non-recent, Dijkstra promoted to RecentEra.

- Add CardanoApiEra shim in Cardano.Api.Extra (temporary, will be
  removed when cardano-api is fully eliminated)
- Replace all RecentEraBabbage patterns with InNonRecentEraBabbage
- Add RecentEraDijkstra error stubs (wallet doesn't support it yet)
- Update test files: remove Babbage-era delegation tests, update
  TransactionSpec imports and pattern matches

The upstream library removed cardano-api dependency (PRs #32, #33).
Breaking changes: CardanoApiEra type family removed, Babbage demoted
from RecentEra to non-recent, Dijkstra promoted to RecentEra.

- Add CardanoApiEra shim in Cardano.Api.Extra (temporary, will be
  removed when cardano-api is fully eliminated)
- Replace all RecentEraBabbage patterns with InNonRecentEraBabbage
- Add RecentEraDijkstra error stubs (wallet doesn't support it yet)
- Update test files: remove Babbage-era delegation tests, update
  TransactionSpec imports and pattern matches

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

Empty stub pages erode reader trust by promising content that doesn't
exist. Delete 18 stubs across all four Diátaxis sections and update
the sidebar accordingly. Topics that need documentation are tracked
for later phases.

Deleted stubs: consensus_protocol, mempool, network_interaction,
starting_up_consensus_layer, genesis_design, managing_updates, ebbs,
storage_layer/{index,immutable_db,volatile_db,ledger_db},
reporting_a_bug, working_with_stored_data/{analysing_a_chain,
serving_a_chain,manipulating_data}, tutorials/{sop,hfc},
references/serialisation.

Also: add one-line descriptions to section index pages, clean up
haddocks.md TODO, fix broken EBB link in ledger_interaction.md.

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

Block arrival now drives chain selection directly: on_block_received
calls try_switch_to(this_block), which walks chain_tree backward to
find the common ancestor with the adopted chain and switches if all
intermediate blocks are cached. No peer chain consultation needed.

Fetch decisions are separate: evaluate_and_fetch examines peer chains
to determine what blocks to request, handles OrphanCandidate
re-intersection, and issues FetchBlockRange commands.

This separation means a node that receives blocks from any source
can immediately apply them without depending on peer chain state
that may be stale or fragmented after rollbacks.

Cluster tested: 25 nodes at p=0.2 for 20 minutes (350+ blocks),
zero stuck nodes. Previously 7-13 nodes would get permanently stuck.

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

Signed-off-by: Chris Gianelloni <[email protected]>

feat(transaction_group): handle subprocess.TimeoutExpired in tx submission

The upstream library removed cardano-api dependency (PRs #32, #33).
Breaking changes: CardanoApiEra type family removed, Babbage demoted
from RecentEra to non-recent, Dijkstra promoted to RecentEra.

- Add CardanoApiEra shim in Cardano.Api.Extra (temporary, will be
  removed when cardano-api is fully eliminated)
- Replace all RecentEraBabbage patterns with InNonRecentEraBabbage
- Add RecentEraDijkstra error stubs (wallet doesn't support it yet)
- Update test files: remove Babbage-era delegation tests, update
  TransactionSpec imports and pattern matches