fix: allow worktree directories through InstanceMiddleware access check

[onnoink]

Issue for this PR

Closes #1504

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Worktree 目录位于 Global.Path.data/worktree/ 下，不在服务器工作目录中。中间件
校验时只检查了 process.cwd()，导致 SDK client 通过 x-mimocode-directory header
携带 worktree 路径的请求被 403 拒绝。本 PR 在中间件校验中额外允许 worktree 根目
录下的路径。

How did you verify your code works?

本地 typecheck 通过，worktree 创建流程中 DirectoryAccessDenied 错误不再触发。

# Run typecheck across all packages
$ source ~/.zshrc && bun turbo typecheck
Attention:
Turborepo now collects completely anonymous telemetry regarding usage.
This information is used to shape the Turborepo roadmap and prioritize features.
You can learn more, including how to opt-out if you'd not like to participate in this anonymous program, by visiting the following URL:
https://turborepo.dev/docs/telemetry
• turbo 2.8.13
• Packages in scope: @mimo-ai/app, @mimo-ai/cli, @mimo-ai/console-app, @mimo-ai/console-core, @mimo-ai/console-function, @mimo-ai/console-mail, @mimo-ai/console-resource, @mimo-ai/desktop, @mimo-ai/enterprise, @mimo-ai/function, @mimo-ai/plugin, @mimo-ai/script, @mimo-ai/sdk, @mimo-ai/shared, @mimo-ai/slack, @mimo-ai/storybook, @mimo-ai/ui, @mimo-ai/web
• Running typecheck in 18 packages
• Remote caching disabled
@mimo-ai/cli:typecheck: cache miss, executing 9fb588ff96c13916
@mimo-ai/console-app:typecheck: cache miss, executing c058abbe45ff87ba
@mimo-ai/plugin:typecheck: cache miss, executing 84061f6412f725df
@mimo-ai/slack:typecheck: cache miss, executing 388e8e066c144874
@mimo-ai/ui:typecheck: cache miss, executing bf8bb27b42f5c46d
@mimo-ai/desktop:typecheck: cache miss, executing 1579b3706db71c46
@mimo-ai/enterprise:typecheck: cache miss, executing 1174f116618602a2
@mimo-ai/shared:typecheck: cache miss, executing ef9b598e9581f4a8
@mimo-ai/app:typecheck: cache miss, executing db2b750d9692495e
@mimo-ai/console-function:typecheck: cache miss, executing 60c1270dd2772144
@mimo-ai/desktop:typecheck: $ tsgo -b
@mimo-ai/cli:typecheck: $ tsgo --noEmit
@mimo-ai/plugin:typecheck: $ tsgo --noEmit
@mimo-ai/ui:typecheck: $ tsgo --noEmit
@mimo-ai/slack:typecheck: $ tsgo --noEmit
@mimo-ai/console-app:typecheck: $ tsgo --noEmit
@mimo-ai/console-function:typecheck: $ tsgo --noEmit
@mimo-ai/shared:typecheck: $ tsgo --noEmit
@mimo-ai/enterprise:typecheck: $ tsgo --noEmit
@mimo-ai/app:typecheck: $ tsgo -b
@mimo-ai/sdk:typecheck: cache miss, executing 7332b1edbb7aa1b4
@mimo-ai/sdk:typecheck: $ tsgo --noEmit
@mimo-ai/console-core:typecheck: cache miss, executing a28e8bafdd6bdc96
@mimo-ai/console-core:typecheck: $ tsgo --noEmit
 Tasks:    12 successful, 12 total
Cached:    0 cached, 12 total
  Time:    9.596s

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR