db: compaction was silently dropping channel and jupe state

compact() rebuilds channels field-by-field, and it omitted several fields, so
automatic log compaction (should_compact -> compact) silently deleted them:
channel url, email, successor, noexpire, the restricted/noautoop/bot_greet/
nobot settings, and every jupe. Emits them all now (settings gated on !=
default via a new PartialEq). Adds a compaction round-trip property test
(compact()+reopen == before) alongside the fold-parity one; both share the
broad build/snapshot helpers.

src/engine/db/mod.rs

@@ -362,7 +362,7 @@ pub struct AjoinEntry {
 
 // A channel's on/off options (ChanServ SET). Typed, not a bag of string flags,
 // so a new option is one field and the compiler proves every place handles it.
-#[derive(Debug, Clone, Copy, Default, Serialize, Deserialize)]
+#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Serialize, Deserialize)]
 pub struct ChanSettings {
     // Append "(requested by <nick>)" to ChanServ KICK reasons.
     #[serde(default)]
@@ -1101,7 +1101,19 @@ impl Db {
             if !c.entrymsg.is_empty() {
                 snapshot.push(Event::ChannelEntryMsgSet { channel: c.name.clone(), msg: c.entrymsg.clone() });
             }
-            if c.settings.signkick || c.settings.private || c.settings.peace || c.settings.secureops || c.settings.keeptopic || c.settings.topiclock {
+            if !c.url.is_empty() {
+                snapshot.push(Event::ChannelUrlSet { channel: c.name.clone(), url: c.url.clone() });
+            }
+            if !c.email.is_empty() {
+                snapshot.push(Event::ChannelEmailSet { channel: c.name.clone(), email: c.email.clone() });
+            }
+            if let Some(s) = &c.successor {
+                snapshot.push(Event::ChannelSuccessorSet { channel: c.name.clone(), successor: Some(s.clone()) });
+            }
+            if c.noexpire {
+                snapshot.push(Event::ChannelNoExpire { channel: c.name.clone(), on: true });
+            }
+            if c.settings != ChanSettings::default() {
                 snapshot.push(Event::ChannelSettingsSet { channel: c.name.clone(), settings: c.settings });
             }
             if !c.topic.is_empty() {
@@ -1182,6 +1194,9 @@ impl Db {
         for e in &self.net.sess_exceptions {
             snapshot.push(Event::SessionExceptionAdded { mask: e.mask.clone(), limit: e.limit, reason: e.reason.clone() });
         }
+        for j in &self.net.jupes {
+            snapshot.push(Event::JupeAdded { name: j.name.clone(), sid: j.sid.clone(), reason: j.reason.clone() });
+        }
         self.log.compact(snapshot)?;
         tracing::info!(before, after = self.log.len(), "compacted event log");
         Ok(())

src/engine/db/tests.rs

@@ -480,10 +480,9 @@
     // Fold parity: the live state after a broad sequence of writes must equal the
     // state rebuilt by replaying the same log — every event's manual live mutation
     // has to match its `apply()` arm, or a restart silently changes the data.
-    #[test]
-    fn live_state_matches_replay_after_a_broad_sequence() {
-        let p = tmp("foldparity");
-        let snapshot = |db: &Db| -> String {
+    // A canonical Debug snapshot of every persisted collection, sorted so the
+    // string is order-independent. Shared by the fold-parity and compaction tests.
+    fn broad_snapshot(db: &Db) -> String {
         let mut a: Vec<_> = db.accounts().cloned().collect();
         a.sort_by(|x, y| x.name.cmp(&y.name));
         let mut c: Vec<_> = db.channels().cloned().collect();
@@ -513,10 +512,10 @@
         op.sort();
         let vt = db.vhost_template().map(str::to_string);
         format!("{a:?}\n{c:?}\n{b:?}\n{gv:?}\n{ak:?}\n{fb:?}\n{of:?}\n{vf:?}\n{jp:?}\n{nw:?}\n{rp:?}\n{hp:?}\n{se:?}\n{op:?}\n{vt:?}")
-        };
+    }
 
-        let live = {
-            let mut db = Db::open(&p, "N1");
+    // Exercise ~45 event types, ending with a drop that must purge references.
+    fn build_broad_state(db: &mut Db) {
         db.scram_iterations = 4096;
         db.register("alice", "pw", Some("a@x.io".into())).unwrap();
             db.register("bob", "pw", None).unwrap();
@@ -574,12 +573,39 @@
         // and group standing — identically in the live path and on replay.
         db.drop_account("alice").unwrap();
         db.drop_channel("#other").unwrap();
-            snapshot(&db)
+    }
+
+    // Fold parity: live state after the sequence == state replayed from the log.
+    #[test]
+    fn live_state_matches_replay_after_a_broad_sequence() {
+        let p = tmp("foldparity");
+        let live = {
+            let mut db = Db::open(&p, "N1");
+            build_broad_state(&mut db);
+            broad_snapshot(&db)
         };
-        let replayed = snapshot(&Db::open(&p, "N1"));
+        let replayed = broad_snapshot(&Db::open(&p, "N1"));
         assert_eq!(live, replayed, "live state must equal the state replayed from the log");
     }
 
+    // Compaction parity: rewriting the log to a snapshot must not lose anything —
+    // the state after compact()+reopen must equal the state before.
+    #[test]
+    fn compaction_preserves_all_state() {
+        let p = tmp("compactparity");
+        {
+            let mut db = Db::open(&p, "N1");
+            build_broad_state(&mut db);
+        }
+        let before = broad_snapshot(&Db::open(&p, "N1"));
+        {
+            let mut db = Db::open(&p, "N1");
+            db.compact().unwrap();
+        }
+        let after = broad_snapshot(&Db::open(&p, "N1"));
+        assert_eq!(before, after, "compaction must preserve every persisted field");
+    }
+
     // Dropping an account erases every reference to it — channel access and
     // successorship, group membership and foundership — so a later re-registration
     // of the same name can't inherit its standing. Holds live and after replay.