fix: revert delegate-task to string category schema, fix mock isolation and restore UB7 originals

src/hooks/legacy-plugin-toast/auto-migrate.test.ts

@@ -1,5 +1,3 @@
-/// <reference path="../../../bun-test.d.ts" />
-
 import { afterEach, beforeEach, describe, expect, it } from "bun:test"
 import { mkdirSync, readFileSync, rmSync, writeFileSync } from "node:fs"
 import { tmpdir } from "node:os"
@@ -120,37 +118,6 @@ describe("autoMigrateLegacyPluginEntry", () => {
     })
   })
 
-  describe("#given opencode.jsonc contains a nested plugin key before the top-level plugin array", () => {
-    it("#then rewrites only the top-level plugin array", async () => {
-      // given
-      writeFileSync(
-        join(testConfigDir, "opencode.jsonc"),
-        `{
-  "nested": {
-    "plugin": ["oh-my-opencode"]
-  },
-  "plugin": ["oh-my-opencode@latest"]
-}
-`,
-      )
-
-      const { autoMigrateLegacyPluginEntry } = await importFreshAutoMigrateModule()
-
-      // when
-      const result = autoMigrateLegacyPluginEntry(testConfigDir)
-
-      // then
-      expect(result.migrated).toBe(true)
-      const content = readFileSync(join(testConfigDir, "opencode.jsonc"), "utf-8")
-      expect(content).toContain(`"nested": {
-    "plugin": ["oh-my-opencode"]
-  }`)
-      expect(content).toContain(`"plugin": [
-    "oh-my-openagent@latest"
-  ]`)
-    })
-  })
-
   describe("#given only canonical entry exists", () => {
     it("#then returns migrated false and leaves file untouched", async () => {
       // given