pika-cloud-runtime-artifacts

The old RuntimeLifecycleLoadError had three decode variants that each carried slightly different context but performed the same role. This step introduces:

1. RuntimeArtifactKind — a Copy enum with variants Status, TerminalResult, and EventStream, each providing a human-readable label() used in error messages.
2. RuntimeArtifactLoadError (renamed from RuntimeLifecycleLoadError) — collapses the three decode variants into a single Decode { kind, source_name, line: Option<usize>, source }. The optional line field is Some only for event-stream decode errors, eliminating the need for a separate DecodeEventLine variant.

The Display implementation now pattern-matches on line: None vs line: Some(line) to choose the appropriate format string, and interpolates kind.label() for the artifact type name. The Error::source() impl likewise simplifies to two arms.

Previously the module exposed twelve free functions with a runtime_/encode_runtime_/decode_runtime_/load_runtime_ naming convention. This step:

1. Creates pub struct RuntimeArtifacts; — a zero-sized unit struct serving purely as a method namespace.
2. Moves all encode/decode/load functions into impl RuntimeArtifacts, dropping the runtime_ prefix since the struct name already conveys context (e.g., decode_runtime_status → RuntimeArtifacts::decode_status).
3. Renames load_runtime_events to RuntimeArtifacts::load_events and refactors its body to call the new decode_event_stream method (renamed from inline logic), passing the RuntimeArtifactKind::EventStream kind.
4. Extracts two private helpers — read_artifact_bytes and read_artifact_string — to DRY up the fs::read / fs::read_to_string calls with consistent RuntimeArtifactLoadError::Read mapping.

The sole surviving free function is runtime_terminal_result_for_exit_code, which constructs a result value and doesn't perform I/O, so it remains at module level.

The pub use lifecycle::{...} block in lib.rs is trimmed from twelve free-function re-exports plus the old error type down to just the types and the single remaining free function. Downstream crates now import RuntimeArtifacts and call methods on it rather than importing individual functions. RuntimeLifecycleLoadError is replaced by RuntimeArtifactLoadError, and the new RuntimeArtifactKind is also exported for callers that need to inspect error details.

The GuestStartupArtifacts struct previously mixed lifecycle artifact paths (status, events, result) with service-management paths (log, PID) in a flat layout. This step:

1. Renames the runtime_artifacts field to lifecycle_artifacts to clarify its purpose.
2. Extracts log_path and pid_path into a new ManagedGuestServiceArtifacts struct, added as a #[serde(flatten)] field called service_artifacts. The log path field is renamed to service_log_path internally with #[serde(rename = "log_path")] to preserve JSON wire compatibility.
3. Moves the path validation for log_path and pid_path out of GuestStartupArtifacts::validate_canonical_paths and into ManagedGuestServiceArtifacts::validate_canonical_paths, following the same pattern as RuntimeArtifactPaths. The parent struct now delegates to both sub-structs.
4. Both Default impls produce the canonical guest paths from the existing constants.

In agent_api.rs, the import of decode_runtime_status_artifact is replaced by RuntimeArtifacts, and the single call site in IncusManagedRuntimeProvider switches to RuntimeArtifacts::decode_status_artifact(...). The associated test decode_runtime_status_artifact_rejects_malformed_snapshot is updated identically.

In managed_openclaw_guest.rs, test assertions that referenced plan.artifacts.runtime_artifacts.* are updated to plan.artifacts.lifecycle_artifacts.* to match the renamed field.

The pikaci executor had three call sites using the old free functions:

1. run_host_local_job — encode_runtime_terminal_result_pretty(&result) becomes RuntimeArtifacts::encode_terminal_result_pretty(&result).
2. run_remote_linux_vm_job — load_runtime_terminal_result(...) becomes RuntimeArtifacts::load_terminal_result(...).
3. run_tart_job — same load_runtime_terminal_result → RuntimeArtifacts::load_terminal_result migration.

The import block drops the two free-function names and adds RuntimeArtifacts instead. No behavioral changes — purely a namespace migration.

Every test in lifecycle.rs and lib.rs that previously called a free function is updated to use RuntimeArtifacts::method() syntax:

• Event round-trip tests — encode_runtime_event_line / decode_runtime_event_line → RuntimeArtifacts::encode_event_line / decode_event_line.
• Status encode/decode tests — encode_runtime_status_pretty / decode_runtime_status → RuntimeArtifacts::encode_status_pretty / decode_status.
• Terminal result tests — all encode/decode/load calls updated.
• Error-path tests — load_runtime_status, load_runtime_terminal_result, load_runtime_events → RuntimeArtifacts::load_status, load_terminal_result, load_events.
• Struct field tests in lib.rs — assertions updated from runtime_artifacts to lifecycle_artifacts and from log_path/pid_path to service_artifacts.service_log_path/service_artifacts.pid_path.
• Validation rejection test — the GuestStartupArtifacts construction in the non-canonical path test uses lifecycle_artifacts as the field name.