fix(model-fallback): align OpenAI fallback resolution across CLI and runtime

Keep install-time and runtime model tables in sync, stop OpenAI-only misrouting when OpenCode Go is present, and add valid OpenAI fallbacks for atlas, metis, and sisyphus-junior.

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

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

src/cli/model-fallback-requirements.test.ts

@@ -0,0 +1,31 @@
+import { describe, expect, test } from "bun:test"
+
+import {
+  CLI_AGENT_MODEL_REQUIREMENTS,
+  CLI_CATEGORY_MODEL_REQUIREMENTS,
+} from "./model-fallback-requirements"
+import { AGENT_MODEL_REQUIREMENTS, CATEGORY_MODEL_REQUIREMENTS } from "../shared/model-requirements"
+
+describe("CLI model fallback requirements", () => {
+  test("agent requirements stay aligned with runtime requirements", () => {
+    // #given
+    const runtimeAgents = AGENT_MODEL_REQUIREMENTS
+
+    // #when
+    const cliAgents = CLI_AGENT_MODEL_REQUIREMENTS
+
+    // #then
+    expect(cliAgents).toEqual(runtimeAgents)
+  })
+
+  test("category requirements stay aligned with runtime requirements", () => {
+    // #given
+    const runtimeCategories = CATEGORY_MODEL_REQUIREMENTS
+
+    // #when
+    const cliCategories = CLI_CATEGORY_MODEL_REQUIREMENTS
+
+    // #then
+    expect(cliCategories).toEqual(runtimeCategories)
+  })
+})