feat(install): add --yes flag for non-interactive SDK installation (EAI-7956)

[r0x0r]

Summary

Adds a --yes flag to rocm install sdk so an SDK install can proceed non-interactively, and makes overwriting an existing managed ROCm SDK an explicit, opt-in action.

• Outside an interactive terminal, reinstalling over an existing SDK now refuses unless --yes is passed, instead of silently clobbering the active runtime.
• A fresh install (no existing SDK) never prompts and is unaffected.
• --yes also continues to approve required system-package installs (e.g. OpenMPI for vLLM) without asking.

Implementation notes

• therock::install_sdk now returns SdkInstallResult { output, mutated }; callers finalize the runtime (finalize_successful_sdk_install) only when the install actually mutated state, rather than keying off dry_run alone.
• The new yes argument is threaded through the install dispatch, the dry-run renderer, and the runtime-update path.

Testing

• cargo test --workspace / cargo clippy --workspace --all-targets -- -D warnings.
• Two e2e scenarios added in tests/e2e-cucumber/features/runtime_setup.feature covering the user-observable behavior:
  • runtime-install-sdk-overwrite-requires-yes (@requires-gpu) — reinstall without --yes is refused with an error explaining --yes is required. The refusal bails before any download, but the precondition (an active runtime) needs a GPU, so it runs on the GPU lane.
  • runtime-install-sdk-overwrite-with-yes (@requires-gpu @nightly) — with --yes the reinstall overwrites and the runtime stays registered/active. Nightly-gated because it performs a real second SDK install.

Both scenarios are GPU/nightly-gated and therefore exercised on the self-hosted GPU and nightly lanes, not the default PR lane.