fix(shared): update category fallback priorities

Align ultrabrain with GPT-5.4 xhigh and move unspecified-high to Opus-first fallback order so category routing reflects the new model policy.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/shared/model-requirements.test.ts

@@ -239,19 +239,19 @@ describe("AGENT_MODEL_REQUIREMENTS", () => {
 })
 
 describe("CATEGORY_MODEL_REQUIREMENTS", () => {
-  test("ultrabrain has valid fallbackChain with gpt-5.3-codex as primary", () => {
+  test("ultrabrain has valid fallbackChain with gpt-5.4 as primary", () => {
     // given - ultrabrain category requirement
     const ultrabrain = CATEGORY_MODEL_REQUIREMENTS["ultrabrain"]
 
     // when - accessing ultrabrain requirement
-    // then - fallbackChain exists with gpt-5.3-codex as first entry
+    // then - fallbackChain exists with gpt-5.4 as first entry
     expect(ultrabrain).toBeDefined()
     expect(ultrabrain.fallbackChain).toBeArray()
     expect(ultrabrain.fallbackChain.length).toBeGreaterThan(0)
 
     const primary = ultrabrain.fallbackChain[0]
     expect(primary.variant).toBe("xhigh")
-    expect(primary.model).toBe("gpt-5.3-codex")
+    expect(primary.model).toBe("gpt-5.4")
     expect(primary.providers[0]).toBe("openai")
   })
 
@@ -326,20 +326,25 @@ describe("CATEGORY_MODEL_REQUIREMENTS", () => {
     expect(primary.providers[0]).toBe("anthropic")
   })
 
-  test("unspecified-high has gpt-5.4 as primary", () => {
+  test("unspecified-high has claude-opus-4-6 as primary and gpt-5.4 as secondary", () => {
     // #given - unspecified-high category requirement
     const unspecifiedHigh = CATEGORY_MODEL_REQUIREMENTS["unspecified-high"]
 
     // #when - accessing unspecified-high requirement
-    // #then - gpt-5.4 is first
+    // #then - claude-opus-4-6 is first and gpt-5.4 is second
     expect(unspecifiedHigh).toBeDefined()
     expect(unspecifiedHigh.fallbackChain).toBeArray()
     expect(unspecifiedHigh.fallbackChain.length).toBeGreaterThan(1)
 
     const primary = unspecifiedHigh.fallbackChain[0]
-    expect(primary.model).toBe("gpt-5.4")
+    expect(primary.model).toBe("claude-opus-4-6")
-    expect(primary.variant).toBe("high")
+    expect(primary.variant).toBe("max")
-    expect(primary.providers).toEqual(["openai", "github-copilot", "opencode"])
+    expect(primary.providers).toEqual(["anthropic", "github-copilot", "opencode"])
+
+    const secondary = unspecifiedHigh.fallbackChain[1]
+    expect(secondary.model).toBe("gpt-5.4")
+    expect(secondary.variant).toBe("high")
+    expect(secondary.providers).toEqual(["openai", "github-copilot", "opencode"])
   })
 
   test("artistry has valid fallbackChain with gemini-3.1-pro as primary", () => {

src/shared/model-requirements.ts

@@ -205,7 +205,7 @@ export const CATEGORY_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
     fallbackChain: [
       {
         providers: ["openai", "opencode"],
-        model: "gpt-5.3-codex",
+        model: "gpt-5.4",
         variant: "xhigh",
       },
       {
@@ -288,16 +288,16 @@ export const CATEGORY_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
   },
   "unspecified-high": {
     fallbackChain: [
-      {
-        providers: ["openai", "github-copilot", "opencode"],
-        model: "gpt-5.4",
-        variant: "high",
-      },
       {
         providers: ["anthropic", "github-copilot", "opencode"],
         model: "claude-opus-4-6",
         variant: "max",
       },
+      {
+        providers: ["openai", "github-copilot", "opencode"],
+        model: "gpt-5.4",
+        variant: "high",
+      },
       { providers: ["zai-coding-plan", "opencode"], model: "glm-5" },
       { providers: ["kimi-for-coding"], model: "k2p5" },
       {