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.

tests/test-stream.ts

@@ -495,6 +495,56 @@ describe("streamCommandCode — request serialization", () => {
     assert.equal(headers["x-session-id"], undefined)
   })
 
+  it("sends developer advisories as user messages in position, without system hoisting", async () => {
+    server.mockResponse({
+      type: "success",
+      events: [JSON.stringify({ type: "finish", finishReason: "stop" })],
+    })
+    const { streamCommandCode } = createTestDeps({ apiBase: server.baseUrl() })
+    const advisory =
+      '<advisory severity="blocker" guidance="weigh, don\'t blindly obey">\nStop and correct the benchmark.\n</advisory>'
+    const context = makeContext({
+      messages: [
+        { role: "user", content: "run the benchmark" },
+        {
+          role: "assistant",
+          content: [
+            { type: "text", text: "running it" },
+            { type: "toolCall", id: "c1", name: "bash", arguments: { command: "bench" } },
+          ],
+        },
+        {
+          role: "toolResult",
+          toolCallId: "c1",
+          toolName: "bash",
+          content: [{ type: "text", text: "benchmark output" }],
+        },
+        { role: "developer", content: advisory },
+        { role: "user", content: "continue" },
+      ],
+    })
+
+    await collectEvents(streamCommandCode(makeModel(), context, { apiKey: "mock-key" }))
+
+    const body = server.lastRequestBody()
+    assert.deepEqual(
+      objectAt(body, ["params", "messages", "3"]),
+      { role: "user", content: advisory },
+      "developer advisory should arrive as an in-position user message with identical content",
+    )
+    assert.deepEqual(objectAt(body, ["params", "messages", "4"]), {
+      role: "user",
+      content: "continue",
+    })
+    assert.equal(objectAt(body, ["params", "messages", "5"]), undefined)
+    assert.equal(
+      objectAt(body, ["params", "system"]),
+      "You are a test assistant.",
+      "advisory must not be hoisted into the system prompt",
+    )
+    assert.doesNotMatch(String(objectAt(body, ["params", "system"])), /advisory/)
+  })
+
   it("accepts the legacy OMP nested reasoning map", async () => {
     server.mockResponse({
       type: "success",