fix(activate): unset inherited hook session vars in IDE env resolution

[Copilot]

In VSCode integrated terminals, project-scope SDK versions still aren't activated on 1.0.10 — vfox current reports the project version but node -v resolves to the global one.

Root cause

VSCode resolves the shell environment by spawning a login shell with VSCODE_RESOLVING_ENVIRONMENT=1, inheriting its own process.env into that shell. When VSCode is launched from a terminal where vfox was already activated, __VFOX_PID / __VFOX_SHELL / __VFOX_CURTMPPATH (and on PowerShell, __VFOX_INITIALIZED) ride along.

renderActivateScript's IDE-resolution branch only omitted these vars from its output — it never unset them. So:

1. The resolution shell exits with the inherited vars still set.
2. VSCode captures them and propagates them to every integrated terminal.
3. In the integrated terminal, vfox activate sees __VFOX_PID, treats it as a live hook session, and env.GetPid() returns the parent shell's PID.
4. SessionSdkDir and env-state.json are therefore the parent shell's — the precmd hook returns the parent's cached PATH (typically global-only) instead of recomputing for the project.
5. On PowerShell specifically, a leaked __VFOX_INITIALIZED additionally causes integrated terminals to skip prompt-hook registration entirely.

This explains the asymmetry: vfox current reads .vfox.toml directly, while node resolves through the leaked cached PATH.

Changes

• internal/env/flag.go: add InitializedFlag constant for __VFOX_INITIALIZED so the hook session keys live in one place.
• cmd/commands/activate.go: in the IsIDEEnvironmentResolution() branch of renderActivateScript, explicitly emit nil (→ unset) for env.HookFlag, env.PidFlag, env.InitializedFlag, and pathmeta.HookCurTmpPath instead of just dropping them from the map. The resolution shell exits with a sanitized environment, so each integrated terminal starts a fresh hook session bound to its own PID and session dir, and PowerShell hook registration runs as expected.
• cmd/commands/activate_test.go: tighten TestRenderActivateScriptForIDEEnvironmentResolutionSkipsHookSessionState to assert unset KEY; is present (and the keys are never re-exported) for all four hook session vars rather than merely absent.

// IDE resolution mode now emits, in addition to PATH and tool vars:
unset __VFOX_SHELL;
unset __VFOX_PID;
unset __VFOX_INITIALIZED;
unset __VFOX_CURTMPPATH;

[codecov]

Codecov Report

❌ Patch coverage is 80.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 24.13%. Comparing base (9522202) to head (16f24b0).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
cmd/commands/activate.go	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #660      +/-   ##
==========================================
- Coverage   25.03%   24.13%   -0.91%     
==========================================
  Files          82       82              
  Lines        5667     7088    +1421     
==========================================
+ Hits         1419     1711     +292     
- Misses       4072     5201    +1129     
  Partials      176      176              

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[Copilot]

Pull request overview

This PR fixes a VS Code/IDE integrated-terminal activation bug caused by hook session variables leaking into IDE environment resolution shells, leading to reuse of a parent shell’s cached PATH/session state instead of recomputing per-project activation.

Changes:

• In IDE environment resolution mode, explicitly emit unsets for __VFOX_SHELL, __VFOX_PID, and __VFOX_CURTMPPATH (via nil values in env.Vars) instead of merely omitting them.
• Update the IDE-resolution activation test to assert unset KEY; is present and that the keys are not re-exported.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
cmd/commands/activate.go	Ensures IDE env-resolution output explicitly unsets inherited hook session variables before returning export-only script.
cmd/commands/activate_test.go	Tightens assertions to require explicit unset statements and prevent re-export of hook session vars.

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[bytemain]

@aooohan 我验证了这个修复没有问题