Store subagent transcripts as separate prompt records

src/authorship/authorship_log.rs

@@ -203,6 +203,9 @@ pub struct PromptRecord {
     /// Full URL to CAS-stored messages (format: {api_base_url}/cas/{hash})
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub messages_url: Option<String>,
+    /// Hash of the parent prompt record (for subagent transcripts)
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub parent_id: Option<String>,
 }
 
 impl Eq for PromptRecord {}
@@ -249,6 +252,7 @@ mod tests {
             accepted_lines: 0,
             overriden_lines: 0,
             messages_url: None,
+            parent_id: None,
         }
     }
 

src/authorship/authorship_log_serialization.rs

@@ -775,6 +775,7 @@ mod tests {
                 accepted_lines: 0,
                 overriden_lines: 0,
                 messages_url: None,
+                parent_id: None,
             },
         );
 
@@ -842,6 +843,7 @@ mod tests {
                 accepted_lines: 0,
                 overriden_lines: 0,
                 messages_url: None,
+                parent_id: None,
             },
         );
 
@@ -891,6 +893,7 @@ mod tests {
                 accepted_lines: 0,
                 overriden_lines: 0,
                 messages_url: None,
+                parent_id: None,
             },
         );
 
@@ -1070,6 +1073,7 @@ mod tests {
                 accepted_lines: 11,
                 overriden_lines: 0,
                 messages_url: None,
+                parent_id: None,
             },
         );
 
@@ -1241,6 +1245,7 @@ mod tests {
                 accepted_lines: 10,
                 overriden_lines: 0,
                 messages_url: None,
+                parent_id: None,
             },
         );
 
@@ -1265,6 +1270,7 @@ mod tests {
                 accepted_lines: 20,
                 overriden_lines: 0,
                 messages_url: None,
+                parent_id: None,
             },
         );