Check whether a byte slice looks like a `SessionEnvelope`. This is a fast check (just the 4-byte magic prefix) that the server can use to identify which changes have session data without fully deserializing. Used during push receipt to index session turns. # Example ```rust use atomic_agent::envelope::SessionEnvelope; let envelope = SessionEnvelope::builder("s1", "claude-code").build(); let by
(data: &[u8])
| 308 | /// assert!(!SessionEnvelope::is_session_envelope(b"ATS")); // too short |
| 309 | /// ``` |
| 310 | pub fn is_session_envelope(data: &[u8]) -> bool { |
| 311 | data.len() >= MAGIC.len() && &data[..4] == MAGIC |
| 312 | } |
| 313 | |
| 314 | /// Returns the number of files changed in this turn. |
| 315 | pub fn turn_file_count(&self) -> usize { |