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/tests/support/worker.rs

@@ -28,6 +28,18 @@ pub const FAST: Tuning = Tuning {
     idle: Duration::from_millis(1),
 };
 
+/// When the tests' ledgers began: before every turn they log (`spoken`).
+pub const BEGAN: &str = "2026-09-28T09:00:00.000Z";
+
+pub fn began() -> Timestamp {
+    Timestamp::parse(BEGAN).unwrap()
+}
+
+/// The ledger line of `BEGAN`, for a test that writes a ledger itself.
+pub fn began_line() -> String {
+    format!(r#"{{"type":"began","time":"{BEGAN}"}}"#)
+}
+
 pub fn config(url: &str) -> HonchoConfig {
     HonchoConfig {
         url: url.to_string(),
@@ -50,12 +62,15 @@ pub struct Home {
 }
 
 impl Home {
+    /// A home whose ledger has begun, at `BEGAN`, as `memoryd` makes it at its first start.
     pub fn new(tag: &str) -> Home {
         let dir = TempDir::new(tag);
         std::fs::create_dir_all(dir.path().join("memory")).unwrap();
+        let mut ledger = Ledger::open(&dir.path().join("memory").join(LEDGER)).unwrap();
+        ledger.append(Record::Began { time: began() }).unwrap();
         Home {
             sync: Arc::new(Mutex::new(TurnSync::new(
-                Ledger::open(&dir.path().join("memory").join(LEDGER)).unwrap(),
+                ledger,
                 "boxmaker0",
                 &dir.path().join("sessions"),
             ))),
@@ -118,12 +133,13 @@ impl Home {
         )
     }
 
-    /// Every record of the ledger on disk, in order.
+    /// Every record of the ledger on disk but its `Began`, in order.
     pub fn records(&self) -> Vec<Record> {
         std::fs::read_to_string(self.ledger_path())
             .unwrap_or_default()
             .lines()
             .map(|l| serde_json::from_str(l).unwrap())
+            .filter(|r| !matches!(r, Record::Began { .. }))
             .collect()
     }