fix(core): preserve developer messages

OMP converts custom and hook messages (advisor notes, todo reminders,
retry nudges) to role "developer" before calling the provider.
messagesToCC() only handled user, assistant, and toolResult, so those
messages were dropped before params.messages was sent to
/alpha/generate. Steering still interrupted pending tools, but the
model never saw the message content.

/alpha/generate has no developer role: the official command-code CLI
(0.32.3) only emits user, assistant, and tool messages plus a separate
params.system. Forward developer messages as user messages with
identical content in the same chronological position. Hoisting them
into params.system would turn a mid-conversation note into a global
top-priority instruction.

src/converters.ts

@@ -190,7 +190,12 @@ export function messagesToCC(
   const pairedToolCallIds = completeToolCallIds(messages)
 
   for (const message of messages ?? []) {
-    if (message.role === "user") {
+    if (message.role === "user" || message.role === "developer") {
+      // Hosts such as OMP steer the agent by injecting developer-role messages
+      // (advisor notes, reminders, nudges) mid-conversation. /alpha/generate
+      // only accepts user, assistant, and tool roles, so degrade the role to
+      // user instead of dropping the message. Content and chronological
+      // position are preserved; system-prompt hoisting would change semantics.
       out.push({
         role: "user",
         content: userContentToCommandCode(message.content, allowImages),