Add Splice adapters for 0.7.x and 0.8.x #339

Context

Upstream Splice has moved past the majors DevKit can bring up. As of 2026-09-13, canton-network/splice tags include 0.8.1 (newest), 0.8.0, and the full 0.7.x line (0.7.0–0.7.5).

DevKit still only registers adapters for majors 0.5 and 0.6 in internal/localnet/adapters.go. The curated catalogue's latest_alias is still 0.6.12 (with 0.6.13 / 0.6.14 catalogued after the refresh-versions fix).

The weekly refresh-versions workflow deliberately skips tags whose major has no adapter, so 0.7 / 0.8 will never auto-catalogue until adapters exist. Cataloguing them first would make Resolve succeed and then fail at adapterFor during localnet up.

Goal

Support running LocalNet on current Splice releases end-to-end:

1. Add internal/splice/v07 (and v08 if 0.8 diverges from 0.7) implementing splice.Adapter.
2. Register the new majors in internal/localnet/adapters.go.
3. Diff upstream cluster/compose/localnet/ for 0.7 / 0.8 vs 0.6.14 and capture compose/env/profile/image differences in the adapters.
4. Catalogue at least one tested tag per new major (e.g. 0.7.5, 0.8.1) via scripts/add-splice-version.sh, set memory floors, and bump latest_alias once validated.
5. Extend refresh-versions.yml supported_majors to include the new majors so weekly auto-PRs cover them.
6. Update CLI/Web UI version picker docs and run integration / e2e against the new tip.

Acceptance criteria

• dpm localnet up <name> --version 0.8.1 (or the chosen tip) completes without --allow-uncurated once catalogued.
• dpm localnet versions shows the new tags as supported.
• Adapter selection for 0.7 / 0.8 does not fall through to the "no adapter registered" error.
• refresh-versions can propose newer 0.7/0.8 tags automatically.
• Docs (docs/versions.md and any published mirror) mention the newly supported majors.

Notes

• Related: refresh-versions currently hardcodes supported_majors="0.5 0.6" next to the adapter registry.
• Issue localnet up reports Splice 0.6.14 ready while splice is still syncing #310 covers readiness/health on 0.6.14 and is separate from adding new major adapters.