feat(model-requirements): prefer GPT-5.4 and glm-5 in agent fallback chains

Align Prometheus, Momus, and Atlas with newer GPT-5.4 fallback tiers and replace Sisyphus install-time GLM-4.7 fallbacks with GLM-5 only.

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

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

src/shared/model-requirements.ts

@@ -101,7 +101,7 @@ export const AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
       },
       {
         providers: ["openai", "github-copilot", "opencode"],
-        model: "gpt-5.2",
+        model: "gpt-5.4",
         variant: "high",
       },
       {
@@ -133,8 +133,8 @@ export const AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
     fallbackChain: [
       {
         providers: ["openai", "github-copilot", "opencode"],
-        model: "gpt-5.2",
-        variant: "medium",
+        model: "gpt-5.4",
+        variant: "xhigh",
       },
       {
         providers: ["anthropic", "github-copilot", "opencode"],
@@ -154,7 +154,7 @@ export const AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
         providers: ["anthropic", "github-copilot", "opencode"],
         model: "claude-sonnet-4-6",
       },
-      { providers: ["openai", "github-copilot", "opencode"], model: "gpt-5.2" },
+      { providers: ["openai", "github-copilot", "opencode"], model: "gpt-5.4", variant: "medium" },
     ],
   },
 };