feat: add member-scoped mcpp run/test editor actions

[Ximiaw]

Summary

• Add mcpp run and mcpp test actions to the editor title bar.
• Scope both visibility and execution to the mcpp project/member containing the active editor file. In a workspace with members A/B/C, editing A runs/tests A with A as the task cwd.
• Hide the actions for files opened outside the current VS Code workspace, non-file editors, and resources without an mcpp project.
• Reuse the existing project resolver and manifest watcher instead of maintaining a workspace-wide findFiles("**/mcpp.toml") flag.
• Rename the existing status-bar shortcut to $(tools) mcpp: 快捷菜单 so it is distinct from the module availability status item.
• Prepare extension version 0.2.5; the release tag must be created from merged main, not from the PR head.

Command semantics

These are project/member-level commands. They invoke fixed mcpp run / mcpp test arguments from the resolved member root. They do not treat the active .cpp file as an independently runnable/testable file; that would require target/test mapping and is a separate feature.

The original editorLangId == cpp condition was insufficient because it exposed generic actions for every C++ file. The current mcpp.inProject context is derived from the active resource and its nearest in-workspace mcpp project instead.

Necessity and compatibility

This is a convenience entry point, not required core functionality: the status-bar quick menu and command palette already expose run/test. Editor-title play/test buttons can still coexist with and visually compete with Code Runner and similar extensions. The member-scoped condition limits incorrect exposure, but it does not eliminate that ecosystem-level title-bar conflict.

Test plan

• npm test: 95 passed
• npm run package: generated mcpp-vscode-0.2.5.vsix
• Verified the packaged VSIX manifest reports version 0.2.5
• Verified packaged dist/src/commands.js contains $(tools) mcpp: 快捷菜单
• Regression coverage includes multi-member selection, workspace boundaries, context refresh, and status-bar naming

Release order

1. Review and merge this PR.
2. Create annotated tag v0.2.5 from the merged main commit.
3. Let .github/workflows/release.yml run tests/package and create or update the Release assets.

[Ximiaw]

作用

在mcpp项目内的编辑器标题栏添加带图标的 run/test 按钮，并通过的 "mcpp.inProject" 上下文让按钮仅在 mcpp 项目中显示。

效果如图

[wellwei]

维护者结论：这个功能属于便捷入口，不是 mcpp 插件的必需核心能力；现有状态栏快捷菜单和命令面板已经能够执行 run/test。

不能只用 editorLangId == cpp（或 =cpp）决定显示。那会让任意 C++ 文件都出现 mcpp 按钮，既可能对非 mcpp 工程执行错误命令，也会与 Code Runner 等多数在编辑器标题栏提供运行按钮的插件产生明显竞争。

本次合并采用的边界是复用现有项目解析逻辑：以当前编辑资源为起点，解析其所在且属于当前 VS Code workspace 的最近 mcpp 工程/member。多 member 工作区 A/B/C 中，编辑 A 的文件只对 A 执行工程级 mcpp run / mcpp test；打开 workspace 外部文件时不显示按钮，也不回退到其他 member 或工作区根。这里的 run/test 是 member 工程级命令，不是“仅运行/测试当前 cpp 文件”。

因此，这个 PR 在限定为 member-aware 的工程级快捷入口后具备可行性；仍需接受其与其他 Code Runner 类扩展在标题栏上的视觉冲突，这是入口位置本身的生态权衡。