memoryd: sync begins when Honcho is turned on, and conclusions are matched by peer

Co-Authored-By: ornith-1.5-35b-a3b <agent@wntrmute.dev>

crates/memoryd/src/honcho/start.rs

@@ -3,12 +3,12 @@
 
 use std::sync::{Arc, Mutex};
 
-use bxcore::SessionId;
+use bxcore::{SessionId, Timestamp};
 
 use crate::config::Config;
 use crate::honcho::client::{Clients, Timeouts};
 use crate::honcho::config::HonchoConfig;
-use crate::honcho::ledger::Ledger;
+use crate::honcho::ledger::{Ledger, Record};
 use crate::honcho::mirror::Mirror;
 use crate::honcho::state;
 use crate::honcho::turns::{LEDGER, TurnSync};
@@ -25,6 +25,20 @@ pub struct Opened {
 }
 
 impl Opened {
+    /// The first time: sync begins now. The `Began` line is written and synced once `memory/`
+    /// exists and before any socket is bound, so every turn reported later is after it.
+    pub fn begin(&self) -> Result<(), StartError> {
+        let sync = self.sync.lock().unwrap_or_else(|p| p.into_inner());
+        let mut ledger = sync.ledger();
+        if ledger.began().is_none() {
+            let began = Record::Began {
+                time: Timestamp::now(),
+            };
+            ledger.append(began).map_err(StartError::Ledger)?;
+        }
+        Ok(())
+    }
+
     /// The memory writes' side of the ledger (task 12).
     pub fn mirror(&self) -> Mirror {
         let ledger = self