test(plugin-handlers): update all plugin handler tests

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

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

src/plugin-handlers/config-handler-formatter.test.ts

@@ -1,7 +1,6 @@
-import { afterEach, beforeEach, describe, expect, spyOn, test } from "bun:test"
+import { afterEach, beforeEach, describe, expect, spyOn, test, mock } from "bun:test"
 
 import type { OhMyOpenCodeConfig } from "../config"
-import { createConfigHandler } from "./config-handler"
 import * as agentConfigHandler from "./agent-config-handler"
 import * as commandConfigHandler from "./command-config-handler"
 import * as mcpConfigHandler from "./mcp-config-handler"
@@ -17,8 +16,26 @@ let applyToolConfigSpy: ReturnType<typeof spyOn>
 let applyMcpConfigSpy: ReturnType<typeof spyOn>
 let applyCommandConfigSpy: ReturnType<typeof spyOn>
 let applyProviderConfigSpy: ReturnType<typeof spyOn>
+let createConfigHandler: (typeof import("./config-handler"))["createConfigHandler"]
+
+async function importFreshConfigHandlerModule(): Promise<typeof import("./config-handler")> {
+  return import(`./config-handler?test=${Date.now()}-${Math.random()}`)
+}
+
+function createPluginConfig(overrides: Partial<OhMyOpenCodeConfig> = {}): OhMyOpenCodeConfig {
+  return {
+    git_master: {
+      commit_footer: true,
+      include_co_authored_by: true,
+      git_env_prefix: "GIT_MASTER=1",
+    },
+    ...overrides,
+  }
+}
+
+beforeEach(async () => {
+  mock.restore()
 
-beforeEach(() => {
   logSpy = spyOn(shared, "log").mockImplementation(() => {})
   loadPluginComponentsSpy = spyOn(
     pluginComponentsLoader,
@@ -47,6 +64,7 @@ beforeEach(() => {
     providerConfigHandler,
     "applyProviderConfig",
   ).mockImplementation(() => {})
+  ;({ createConfigHandler } = await importFreshConfigHandlerModule())
 })
 
 afterEach(() => {
@@ -57,12 +75,13 @@ afterEach(() => {
   applyMcpConfigSpy.mockRestore()
   applyCommandConfigSpy.mockRestore()
   applyProviderConfigSpy.mockRestore()
+  mock.restore()
 })
 
 describe("createConfigHandler formatter pass-through", () => {
   test("preserves formatter object configured in opencode config", async () => {
     // given
-    const pluginConfig: OhMyOpenCodeConfig = {}
+    const pluginConfig = createPluginConfig()
     const formatterConfig = {
       prettier: {
         command: ["prettier", "--write"],
@@ -98,7 +117,7 @@ describe("createConfigHandler formatter pass-through", () => {
 
   test("preserves formatter=false configured in opencode config", async () => {
     // given
-    const pluginConfig: OhMyOpenCodeConfig = {}
+    const pluginConfig = createPluginConfig()
     const config: Record<string, unknown> = {
       formatter: false,
     }