fix: trace-hook.ps1 - Copilot hooks under PowerShell on Windows no longer open the choose-an-app dialog (#164)

Files changed:
- CHANGES.md
- EVALS.md
- VERSION
- tools/README.md
- tools/chemenu/tests/test_preflight.py
- tools/chemenu/tests/test_preflight_pwsh.py
- tools/trace-hook
- tools/trace-hook.ps1

EVALS.md

@@ -158,7 +158,7 @@ own decision-document schema verified against a live CLI first (this repo has no
 unverified, per the same rule that governed the Vibe adapter: an adapter that cannot be verified
 is not written.
 
-Three details in that file are load-bearing, and the first holds for all three hook
+Four details in that file are load-bearing, and the first two hold for all three hook
 configurations:
 
 - **The interpreter is the venv's, never the script's shebang.** Each `bash` command is
@@ -169,6 +169,14 @@ configurations:
   (`python3`) was the Microsoft Store alias in Git Bash on Windows, which made every hook there
   a silent no-op. Before the preflight has created the venv, `trace-hook` records nothing and
   exits 0.
+- **`./tools/trace-hook` has a PowerShell twin, `tools/trace-hook.ps1`.** PowerShell on
+  Windows resolves the string to the `.ps1` first; without one, it hands the sh script to a
+  file association and Windows asks which app should open it - on every hook event. A `bash`
+  field alone does not keep the string out of PowerShell: Copilot CLI also reads
+  `.claude/settings.json` and runs its single `command` under PowerShell on Windows. The twin
+  keeps the sh script's rules - venv Python, silent without a venv, exit 0 whatever happens -
+  and avoids `#Requires -Version 7`, because VS Code starts hooks under Windows PowerShell 5.1.
+  Each `powershell` command here is written so 5.1 can parse it, too.
 - **Every command ends in `|| true`.** `preToolUse` hooks are *fail-closed*: a non-zero exit
   denies the tool call. Without the guard, a missing interpreter would turn the observer into
   a blocker that refuses every tool call in the session. (Timeouts are fail-open, so the