channels: replace Member's six parallel prefix bools (oprefix/owner/admin/op/halfop/voice) with a single u8 bitfield (PFX_*) + inline bool accessors/mutators — same semantics, one byte instead of six, no more risk of the flags drifting out of sync; all call sites go through op()/set_op()-style methods

src/modules/rpc/channel.rs

@@ -10,11 +10,11 @@ use crate::server::{now, Server};
 fn prefixes(m: &crate::channels::Member) -> String {
     let mut p = String::new();
     for (has, ch) in [
-        (m.owner, '~'),
-        (m.admin, '&'),
-        (m.op, '@'),
-        (m.halfop, '%'),
-        (m.voice, '+'),
+        (m.owner(), '~'),
+        (m.admin(), '&'),
+        (m.op(), '@'),
+        (m.halfop(), '%'),
+        (m.voice(), '+'),
     ] {
         if has {
             p.push(ch);