fix(ci): simplify test runner to plain bun test by fixing mock.module() leakage

- Add afterAll(() => { mock.restore() }) to 52 test files missing cleanup
- Rewrite create-tool-guard-hooks.test.ts to use spyOn instead of barrel mock
- Fix skill-mcp-manager OAuth tests with missing mockTokens/mockLogin definitions
- Fix start-work hook: show worktree active block on resume with existing worktree_path
- Extract createWorktreeActiveBlock to worktree-block.ts to avoid circular import
- Replace 80-line isolated test runner CI config with single `bun test` command

src/hooks/atlas/tool-execute-after-background-launch.test.ts

@@ -1,6 +1,6 @@
 /// <reference types="bun-types" />
 
-import { afterEach, beforeEach, describe, expect, it, mock } from "bun:test"
+import { afterEach, beforeEach, describe, expect, it, mock, afterAll } from "bun:test"
 import { existsSync, mkdirSync, rmSync } from "node:fs"
 import { tmpdir } from "node:os"
 import { join } from "node:path"
@@ -23,6 +23,8 @@ mock.module("../../shared/git-worktree", () => ({
   formatFileChanges: mock(() => "No file changes"),
 }))
 
+afterAll(() => { mock.restore() })
+
 const { createToolExecuteAfterHandler } = await import("./tool-execute-after")
 
 describe("createToolExecuteAfterHandler background launch detection", () => {