fix: normalize xhigh aliases and docs sync (#9976)

docs/tools/thinking.md

@@ -16,7 +16,7 @@ title: "Thinking Levels"
   - medium → “think harder”
   - high → “ultrathink” (max budget)
   - xhigh → “ultrathink+” (GPT-5.2 + Codex models only)
-  - `x-high` and `extra-high` map to `xhigh`.
+  - `x-high`, `x_high`, `extra-high`, `extra high`, and `extra_high` map to `xhigh`.
   - `highest`, `max` map to `high`.
 - Provider notes:
   - Z.AI (`zai/*`) only supports binary thinking (`on`/`off`). Any non-`off` level is treated as `on` (mapped to `low`).

src/auto-reply/thinking.test.ts

@@ -11,8 +11,23 @@ describe("normalizeThinkLevel", () => {
     expect(normalizeThinkLevel("mid")).toBe("medium");
   });
 
-  it("accepts xhigh", () => {
+  it("accepts xhigh aliases", () => {
     expect(normalizeThinkLevel("xhigh")).toBe("xhigh");
+    expect(normalizeThinkLevel("x-high")).toBe("xhigh");
+    expect(normalizeThinkLevel("x_high")).toBe("xhigh");
+    expect(normalizeThinkLevel("x high")).toBe("xhigh");
+  });
+
+  it("accepts extra-high aliases as xhigh", () => {
+    expect(normalizeThinkLevel("extra-high")).toBe("xhigh");
+    expect(normalizeThinkLevel("extra high")).toBe("xhigh");
+    expect(normalizeThinkLevel("extra_high")).toBe("xhigh");
+    expect(normalizeThinkLevel("  extra high  ")).toBe("xhigh");
+  });
+
+  it("does not over-match nearby xhigh words", () => {
+    expect(normalizeThinkLevel("extra-highest")).toBeUndefined();
+    expect(normalizeThinkLevel("xhigher")).toBeUndefined();
   });
 
   it("accepts extra-high aliases as xhigh", () => {