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/shared/model-error-classifier.test.ts

@@ -1,5 +1,5 @@
 declare const require: (name: string) => any
-const { describe, expect, test, beforeEach, mock } = require("bun:test")
+const { describe, expect, test, beforeEach, mock, afterAll } = require("bun:test")
 
 const readConnectedProvidersCacheMock = mock(() => null)
 
@@ -7,6 +7,8 @@ mock.module("./connected-providers-cache", () => ({
   readConnectedProvidersCache: readConnectedProvidersCacheMock,
 }))
 
+afterAll(() => { mock.restore() })
+
 import { shouldRetryError, selectFallbackProvider } from "./model-error-classifier"
 
 describe("model-error-classifier", () => {