test(04-01): add Athena registration and schema regressions

- verify Athena primary agents honor uiSelectedModel and override precedence

- add schema tests to lock athena acceptance in builtin and overridable names

src/config/schema/agent-names.test.ts

@@ -1,4 +1,5 @@
 import { describe, expect, test } from "bun:test"
+import { BuiltinAgentNameSchema, OverridableAgentNameSchema } from "./agent-names"
 import { OhMyOpenCodeConfigSchema } from "./oh-my-opencode-config"
 
 describe("OhMyOpenCodeConfigSchema disabled_skills", () => {
@@ -21,3 +22,27 @@ describe("OhMyOpenCodeConfigSchema disabled_skills", () => {
     }
   })
 })
+
+describe("agent name schemas", () => {
+  test("BuiltinAgentNameSchema accepts athena", () => {
+    //#given
+    const candidate = "athena"
+
+    //#when
+    const result = BuiltinAgentNameSchema.safeParse(candidate)
+
+    //#then
+    expect(result.success).toBe(true)
+  })
+
+  test("OverridableAgentNameSchema accepts athena", () => {
+    //#given
+    const candidate = "athena"
+
+    //#when
+    const result = OverridableAgentNameSchema.safeParse(candidate)
+
+    //#then
+    expect(result.success).toBe(true)
+  })
+})