fix(omp): read the model omp names in its own model_change entries

changelog.d/omp-model-change-name.md

@@ -0,0 +1,3 @@
+### Fixed
+- An Oh My Pi chat keeps showing its model after `/model` switches it, instead of losing the name
+  until the next answer. Found in #1250 by @CharleoYang.

server/conversation-metadata.test.ts

@@ -60,6 +60,15 @@ describe("recorded conversation model settings", () => {
     }
   });
 
+  it("reads omp's own model change, which names provider/id in one field", () => {
+    expect(parseConversationMetadata(jsonl(
+      { type: "message", message: { role: "assistant", model: "claude-opus-5-5", provider: "anthropic" } },
+      { type: "model_change", model: "openai-codex/gpt-5.6-sol" },
+    ), "omp-transcript")).toEqual({ model: "gpt-5.6-sol", reasoning_effort: null });
+    expect(parseConversationMetadata(jsonl({ type: "model_change", model: "local-model" }), "omp-transcript"))
+      .toEqual({ model: "local-model", reasoning_effort: null });
+  });
+
   it("reads Claude's actual model without deriving effort from thinking content", () => {
     expect(parseConversationMetadata(jsonl(
       { type: "assistant", message: { role: "assistant", model: "claude-test", content: [{ type: "thinking", thinking: "text" }] } },

server/conversation-metadata.ts

@@ -70,7 +70,14 @@ export function parseConversationMetadata(text: string, source: ConversationResp
       // A new complete context without effort must not retain an older value.
       if (model || effort !== undefined) metadata.reasoning_effort = label(effort);
     } else if (source === "omp-transcript" || source === "omo-transcript" || source === "gjc-transcript" || source === "pi-transcript") {
-      if (entry.type === "model_change") { metadata.model = label(entry.modelId); piProvider = label(entry.provider); }
+      if (entry.type === "model_change") {
+        // pi and omo name `provider` and `modelId`; omp names one `model`, "provider/id", where
+        // the id is what its answers name as their model
+        const named = label(entry.model);
+        const slash = named?.indexOf("/") ?? -1;
+        metadata.model = label(entry.modelId) ?? (slash > 0 ? named!.slice(slash + 1) : named);
+        piProvider = label(entry.provider) ?? (slash > 0 ? named!.slice(0, slash) : null);
+      }
       if (entry.type === "thinking_level_change") metadata.reasoning_effort = label(entry.thinkingLevel);
       const message = piMessage(entry) ?? {};
       // a turn answers at whatever model it ran at, and that is the one the window belongs to