Cardano Updates

Implementation pre-flight on dce6abbbf1 showed that swapping the cert
callsites in Shelley/Transaction.hs to the *Ledger variants does not
compile: mkUnsignedTransaction passes the cert lists into
constructUnsignedTx (the cardano-api body builder) at line ~834, which
expects [ApiCert.Certificate (CardanoApiEra era)]. The *Ledger builders
return [Ledger.TxCert era]. The two are not interchangeable at this
callsite.

Cardano/Wallet.hs works on *Ledger because it routes through
constructUnsignedTxLedger — a different code path. The original Phase-0
inventory missed which body builder consumed the certs in
Shelley/Transaction.hs.

Net: Story 1 is blocked transitively on Story 2 (the body-construction
migration to constructUnsignedTxLedger), which is itself blocked on the
minting + script-witness AC in #5243. When Story 2 lands, the helper
deletion + cabal prune fold into Story 2's commit; there is no
standalone Story 1 PR. PR #5286 becomes documentation-only.

Files updated:
- spec.md: Story 1 marked BLOCKED on Story 2; assumption section corrected.
- plan.md: Status block reflects all three stories deferred; Vertical
  Slice Contract rewritten so Story 1 folds into Story 2.
- research.md: new §G "Cert flow in Shelley/Transaction.hs — what
  blocks Story 1" with the GHC error and the call-graph analysis.
- data-model.md: Story 1 row corrected to note it is not downstream-
  compatible at the Shelley/Transaction.hs callsites today.
- contracts/module-interface-invariants.md: helper-deletion invariants
  re-pegged to Story 2.
- quickstart.md: stub explaining the deferral and what to do when
  Story 2 unblocks.
- tasks.md: no work tasks; the prior T001-T014 are removed in favour of
  a deferral notice.

Refs: #5285, #5243, #5237

Spec under specs/006-drop-api-shelley-tx/ covering issue #5285:
three independently-shippable vertical stories (P1 cert helpers,
P2 body construction, P3 signTransaction) under parent epic #5237.

Use a short mktemp directory under /tmp for the Linux Memory Benchmark before running the existing benchmark command. This avoids the cardano-node Unix socket path limit while keeping other benchmark jobs on runner.temp.

Ignore local llm review artifacts and remove the tracked llm review file inherited from the rebased base so the repository keeps llm out of tracked source.

Verification: actionlint accepted linux-benchmarks.yml with repository custom runner-label warnings ignored. The representative issue path is 120 bytes, and the new representative socket path is 94 bytes.

Live verification: Linux Benchmarks workflow dispatch 25724369765 passed end to end and uploaded memory-bench-results.csv, memory.hp, memory.svg, memory.log, and memory.error.log.

Fixes #5283

Closes #5278.

Reworks `.github/workflows/restoration-benchmarks.yml` so every
restoration benchmark run starts from a fresh Mithril-provisioned node
database instead of relying on whatever the self-hosted runner happens
to have on disk. Each matrix leg (`base`, `seq0`, `seq1`, `rnd5`) gets
an isolated node DB so legs can run in parallel without sharing mutable
state. Mithril download/extraction/node startup/sync are timed and
logged separately from the wallet restoration benchmark.

## Status

Draft. Only the feature spec is in so far
(`specs/005-mithril-bench-snapshots/spec.md`). Plan, tasks, and
implementation follow as separate commits on this branch.

Record the solo PR gate, plan review, task review, code handoff, and ReadyForExternalReview state for issue #5283.

The reviewed code commit is 60805e8907c38eeb4027ce399d881e7756914510.

Use a short mktemp directory under /tmp for the Linux Memory Benchmark before running the existing benchmark command. This avoids the cardano-node Unix socket path limit while keeping other benchmark jobs on runner.temp.

Gate: llm/reviews/local-5283-linux-memory-benchmark-tmpdir/gate.sh (old path 120 bytes, new path 94 bytes).

Fixes #5283

Closes #5278

Closes #5278

Validate the cardano-wallet package as the next dependency-first slice.
No owned source changes were required; the patch records formatting,
linting, component builds for the library, public sublibrary, executables,
and the green wallet-key-export test result.

Validate delta-store as the next dependency-first slice. No owned source
changes were required; the patch records formatting, linting, Nix
package/check builds, and the green unit test result.

Validate cardano-wallet-network-layer as the next dependency-first
slice. No owned source changes were required; the patch records
formatting, linting, Nix package/check builds, and the green unit test
result.

Validate iohk-monitoring-extra as the next dependency-first slice. The
package declares no Cabal test-suite, so the patch records formatting,
linting, cabal formatting, and the Nix library build gate.

Validate cardano-api-extra as the next dependency-first slice. The
package declares no Cabal test-suite, so the patch records formatting,
linting, cabal formatting, and the Nix library build gate.

Validate address-derivation-discovery as the next dependency-first
slice. The package declares no Cabal test-suite, so the patch records
formatting, linting, cabal formatting, and the Nix library build gate.