Cardano Updates

cabal.project: add source-repository-package stanza for hermod-tracing PR #9
  (Rename NodeStartupInfo.suiEra to suiLatestSupportedEra), commit 4a3baa5e

NodeStartupInfo.hs: update documentFor to reflect new field name and meaning
EraSettings.hs: update suiEra -> suiLatestSupportedEra at call site

- wallet-key-export.hs: pattern-match HashedCredentials instead of
  tuple; V2 keys exit with a clear error (no XPrv export possible)
- wallet-key-export-test.hs: wrap serializeXPrv args in HashedCredentialsV1
- PersistPrivateKeySpec.hs: bind IO-returning encryptedCreate with >>=
- LayerSpec.hs: remove now-redundant XPrv import (Werror)
- Cardano.Wallet: use encryptedChainCode in decryptV2 to supply the
  missing 32-byte chain code so CC.xprv receives the full 96 bytes

turtle ^>= 1.6.x requires optparse-applicative < 0.19, conflicting with
the rest of the project. allow-newer would satisfy the solver but turtle
1.6.x fails to compile against 0.19 because of the breaking Doc type
change (ansi-wl-pprint -> prettyprinter).

Replace turtle usage with standard IO:
- Shell monad -> plain list IO with mapM/concat
- options/optPath/argPath/argText -> execParser/strOption/argument directly
- Pattern URL parser -> Text.breakOn/stripPrefix in Maybe monad
- printf/format -> Text concatenation and hPutStrLn stderr
- die -> exitFailure helper

Also drops foldl and prettyprinter which were only needed via turtle.

CPS Frontmatter Discussions fix

The per-slot memory telemetry added in 8bc4da50e was silently lost when
resolving conflicts during the "Merged with github main" merge
(da54b615c): the NodeEvent enum and main.rs took main's side, discarding
the MemorySizes additions. The shared-consensus state_sizes() snapshots
and LeiosStoreStats survived, but nothing assembled them into an event,
so scripts/memory-report.py reported "no MemorySizes events found".

Re-applies the net-node / net-core wiring against the post-merge tree:

  - telemetry.rs: NodeEvent::MemorySizes(Box<MemorySizesPayload>) plus
    the MemorySizesPayload and FragmentSizes structs and their test.
  - consensus/mod.rs: praos_state_sizes() / leios_state_sizes() wrappers.
  - coordinator.rs: per-peer fragment_sizes snapshot, kept in sync on
    every fragment mutation (intersection, header announce, rollback,
    add/remove peer); exposed through the handle.
  - mod.rs: CoordinatorHandle gains leios_store + fragment_sizes so the
    app can read sizes without a command round-trip.
  - main.rs: emit one MemorySizes event per slot.
  - Cargo.lock: reflect net-core's existing serde dependency.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>