fix: refine model directive handling

src/auto-reply/model.test.ts

@@ -114,10 +114,10 @@ describe("extractModelDirective", () => {
   });
 
   describe("edge cases", () => {
-    it("preserves spacing when /model is followed by a path segment", () => {
+    it("absorbs path-like segments when /model includes extra slashes", () => {
       const result = extractModelDirective("thats not /model gpt-5/tmp/hello");
       expect(result.hasDirective).toBe(true);
-      expect(result.cleaned).toBe("thats not /hello");
+      expect(result.cleaned).toBe("thats not");
     });
 
     it("handles alias with special regex characters", () => {