v0.42.0

Runner

• Harness-native provider selection (#157): the runner keys binary selection off the resolved harness attribute when present (e.g. harness=agy → the Antigravity agy CLI), falling back to provider when absent. The legacy provider=agy-cli token is still accepted as an alias for one release (backward-compatible; in-flight payloads unaffected).

Landing serializer (FD-4)

• Hardening (#158): per-proposal isolated git worktrees so parallel batch members no longer share a working tree; integer-sequence FIFO tiebreak for sub-second enqueues; compare-and-delete lock release via an atomic Lua script (a worker can only release its own lock).

Tests

• De-flaked the daemon child-output slog test under -race — poll/notify instead of fixed waits (#156).