Function persist_session_diffs

crates/opencode-session/src/summary.rs:237–246

Persist session-level diff results in session metadata. This is the Rust rewrite equivalent of TS `Storage.write(["session_diff", sessionID], diffs)`.

(
    session: &mut Session,
    session_id: &str,
    diffs: &[SummaryFileDiff],
)

/// Persist session-level diff results in session metadata.
/// This is the Rust rewrite equivalent of TS `Storage.write(["session_diff", sessionID], diffs)`.
pub fn persist_session_diffs(
    session: &mut Session,
    session_id: &str,
    diffs: &[SummaryFileDiff],
) -> anyhow::Result<()> {
    let key = session_diff_storage_key(session_id);
    let value = serde_json::to_value(diffs)?;
    session.metadata.insert(key, value);
    Ok(())
}

/// Load persisted session-level diff results from session metadata.
pub fn load_session_diffs(session: &Session, session_id: &str) -> Vec<SummaryFileDiff> {