nickserv: add SET (password/email) and DROP

SET PASSWORD changes your password (derived off-thread like register) and
SET EMAIL sets an address. DROP deletes your account, releases and drops
the channels you founded, and logs you out. A dropped account federates,
and each node logs out any local session that was relying on it.

modules/protocol/inspircd.rs

@@ -280,8 +280,8 @@ impl Protocol for InspIrcd {
                 vec![format!(":{} INVITE {} {} 1 0", from, uid, channel)]
             }
             NetAction::Raw(s) => vec![s.clone()],
-            // Internal: the link layer handles this before serialization.
-            NetAction::DeferRegister { .. } => vec![],
+            // Internal: the link layer handles these before serialization.
+            NetAction::DeferRegister { .. } | NetAction::DeferPassword { .. } => vec![],
         }
     }
 

modules/protocol/mod.rs

@@ -68,6 +68,9 @@ pub enum NetAction {
     // still needs its (expensive) key derivation. The link layer runs the
     // derivation off-thread, then calls Engine::complete_register.
     DeferRegister { account: String, password: String, email: Option<String>, reply: RegReply },
+    // Internal only: a password change awaiting the same off-thread derivation.
+    // The link layer derives, then calls Engine::complete_password_change.
+    DeferPassword { account: String, password: String, agent: String, uid: String },
 }
 
 // How to answer a registration once its credentials have been derived.