Plugin: ensure-venv fails SessionStart on Python < 3.11 even when the plugin venv will not be used

[bgausden]

Problem

The SessionStart hook runs ensure-venv.sh / ensure-venv.bat unconditionally, and both start with a Python ≥ 3.11 guard (sh L28–35, bat L32–39) that exits 1.

Since 8e914e4, slm-launch under the default SLM_LAUNCHER=auto uses an installed slm and never touches the plugin venv. On a host where SLM is installed in its own environment but the first python3 on PATH is older (e.g. macOS system Python 3.9), every session start reports a Python-version error for a venv that is never used.

Proposed change

Before the guard, exit 0 when the launcher will not use the plugin venv, using the same decision as slm-launch:

SLM_LAUNCHER	Bootstrap?
plugin	yes
auto / unset, slm on PATH	skip
auto / unset, no slm on PATH	yes
system or a path	skip

A skip must not be based on "a daemon is running": under auto with no PATH slm, the launcher still execs the plugin venv even when a daemon is up.

The POSIX half is implemented and tested on a fork (commit in barrygfox/superlocalmemory, happy to open a PR). The Windows half depends on the Windows launcher issue (#139), because today slm-launch.bat always uses the venv and any skip would leave it without slm.exe.

Acceptance criteria

• ensure-venv.sh with SLM_LAUNCHER unset, a fake slm on PATH and a python3 < 3.11 first on PATH exits 0 and creates no $CLAUDE_PLUGIN_DATA/venv.
• ensure-venv.sh with SLM_LAUNCHER=system or SLM_LAUNCHER=/some/path exits 0 and creates no venv.
• ensure-venv.sh with SLM_LAUNCHER=plugin and python3 < 3.11 still exits 1 with the existing error (existing test test_rejects_python_less_than_3_11 passes).
• Same three cases hold for ensure-venv.bat (structural tests in test_wf_windows_crossplatform.py), landed only after Plugin (Windows): slm-launch.bat always runs the plugin venv — add SLM_LAUNCHER selection to match POSIX #139.
• plugin/ and copilot-plugin/ copies are regenerated; build-plugin.mjs --check and build-copilot-plugin.mjs --check pass.

Dependencies

• Windows part blocked by Plugin (Windows): slm-launch.bat always runs the plugin venv — add SLM_LAUNCHER selection to match POSIX #139.

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This issue was generated by an AI assistant (Claude) from a read of the code at 5bfa47c, and reviewed by a human before posting.

[bgausden]

Note for the Windows half of this issue: #139 now questions whether ensure-venv.bat is ever run. Claude Code runs command hooks with bash (Git Bash) or, without Git Bash, PowerShell — never cmd — and the SessionStart hook references ensure-venv.sh explicitly. So on Windows with Git for Windows, the .sh skip-check is the one that matters, and it would need to find slm on the Git Bash PATH. The .bat criterion here should wait on the outcome of #139.

The POSIX half is unaffected.

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This comment was generated by an AI assistant (Claude) and reviewed by a human before posting.