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/serve.rs

@@ -93,8 +93,8 @@ enum Which {
 }
 
 /// With `[honcho]`, read the ledger through and the keys first. Then create what is missing
-/// under `memory/`, open the index and catch it up, bind the three sockets, and start the Honcho
-/// worker. The error names what failed.
+/// under `memory/` (and, the first time, write when sync began), open the index and catch it up,
+/// bind the three sockets, and start the Honcho worker. The error names what failed.
 pub fn start(config: Config, log: Log) -> Result<Running, StartError> {
     let opened = match config.honcho_config()? {
         Some(honcho) => Some(worker::open(&config, &honcho, &log)?),
@@ -102,6 +102,9 @@ pub fn start(config: Config, log: Log) -> Result<Running, StartError> {
     };
     let store = Store::new(&config.memory_dir());
     store.init(&config.memory.soul_starter)?;
+    if let Some(opened) = &opened {
+        opened.begin()?;
+    }
     let index = Index::open(&config.index_path(), config.index.max_class)?;
     let (_counts, problems) = index.catch_up(&config.sessions_dir(), &store.path("notes.md"))?;
     for problem in problems {