persist replay state and move CommitDiff types to fiber-types

[jjyr]

Summary

• persist pending_replay_updates and last_was_revoke in ChannelActorData main serialization format
• keep non-serializable runtime-only fields in ChannelActorState wrapper
• move CommitDiff, CommitmentSignedTemplate, and ReplayOrderHint into fiber-types

Validation

• cargo fmt --all
• cargo check -p fnn --locked
• cargo nextest run -p fnn test_commit_diff_roundtrip_v2 test_validate_commit_diff_for_replay test_channel_actor_state_store test_store_sample_channel_actor_state test_channel_actor_state_samples_roundtrip test_serde_channel_actor_state_ciborium --no-fail-fast
• cargo clippy --all-targets --all-features -p fnn -p fiber-bin -- -D warnings