Fix duration overflow, expiry-warned resets, DICT control-char injection, and HostServ TAKE forbid recheck

src/engine/db/account.rs

@@ -734,6 +734,7 @@ impl Db {
             let _ = self.log.append(Event::AccountSeen { account: account.to_string(), ts: now });
             if let Some(a) = self.accounts.get_mut(&k) {
                 a.last_seen = a.last_seen.max(now);
+                a.expiry_warned = false; // mirror the AccountSeen fold, or a re-active account never re-warns
             }
         }
     }
@@ -747,6 +748,7 @@ impl Db {
             let _ = self.log.append(Event::ChannelUsed { channel: channel.to_string(), ts: now });
             if let Some(c) = self.channels.get_mut(&k) {
                 c.last_used = c.last_used.max(now);
+                c.expiry_warned = false; // mirror the ChannelUsed fold, or a re-active channel never re-warns
             }
         }
     }

src/engine/db/mod.rs

@@ -1258,6 +1258,11 @@ impl Db {
             if c.noexpire {
                 snapshot.push(Event::ChannelNoExpire { channel: c.name.clone(), on: true });
             }
+            if c.expiry_warned {
+                // Preserve the "warning already sent" flag, or compaction re-arms it
+                // and the idle channel is warned again on the next sweep.
+                snapshot.push(Event::ChannelExpiryWarned { channel: c.name.clone() });
+            }
             if c.settings != ChanSettings::default() {
                 snapshot.push(Event::ChannelSettingsSet { channel: c.name.clone(), settings: c.settings });
             }