fix(hooks): rewrite install_hook_wrapper.ps1 to avoid argv-dup bug

Under Claude Code v2.1.116 the first argv token of a hook command is
duplicated. When the token is a quoted Windows .exe path, bash.exe is
re-invoked with itself as script (exit 126). PR #1524 fixed the shape
of settings.local.json; this script keeps the installer consistent so
re-running it does not regenerate the broken form.

Changes:
- First token is now PATH-resolved `bash` instead of the quoted bash.exe
- Wrapper path is normalized to forward slashes for MSYS safety
- PreToolUse and PostToolUse get distinct pre/post positional arguments
- JSON output is written with LF endings (no mixed CRLF/LF)

Companion doc: docs/fixes/INSTALL-HOOK-WRAPPER-FIX-20260422.md

docs/fixes/INSTALL-HOOK-WRAPPER-FIX-20260422.md

@@ -0,0 +1,53 @@
+# install_hook_wrapper.ps1 argv-dup bug workaround (2026-04-22)
+
+## Summary
+
+`docs/fixes/install_hook_wrapper.ps1` is the PowerShell helper that copies
+`observe-wrapper.sh` into `~/.claude/skills/continuous-learning/hooks/` and
+rewrites `~/.claude/settings.local.json` so the observer hook points at it.
+
+The previous version produced a hook command of the form:
+
+```
+"C:\Program Files\Git\bin\bash.exe" "C:\Users\...\observe-wrapper.sh"
+```
+
+Under Claude Code v2.1.116 the first argv token is duplicated. When that token
+is a quoted Windows executable path, `bash.exe` is re-invoked with itself as
+its `$0`, which fails with `cannot execute binary file` (exit 126). PR #1524
+documents the root cause; this script is a companion that keeps the installer
+in sync with the fixed `settings.local.json` layout.
+
+## What the fix does
+
+- First token is now the PATH-resolved `bash` (no quoted `.exe` path), so the
+  argv-dup bug no longer passes a binary as a script.
+- The wrapper path is normalized to forward slashes before it is embedded in
+  the hook command, avoiding MSYS backslash handling surprises.
+- `PreToolUse` and `PostToolUse` receive distinct commands with explicit
+  `pre` / `post` positional arguments, matching the shape the wrapper expects.
+- The settings file is written with LF line endings so downstream JSON parsers
+  never see mixed CRLF/LF output from `ConvertTo-Json`.
+
+## Resulting command shape
+
+```
+bash "C:/Users/<you>/.claude/skills/continuous-learning/hooks/observe-wrapper.sh" pre
+bash "C:/Users/<you>/.claude/skills/continuous-learning/hooks/observe-wrapper.sh" post
+```
+
+## Usage
+
+```powershell
+# Place observe-wrapper.sh next to this script, then:
+pwsh -File docs/fixes/install_hook_wrapper.ps1
+```
+
+The script backs up `settings.local.json` to
+`settings.local.json.bak-<timestamp>` before writing.
+
+## Related
+
+- PR #1524 — settings.local.json shape fix (same argv-dup root cause)
+- PR #1511 — skip `AppInstallerPythonRedirector.exe` in observer python resolution
+- PR #1539 — locale-independent `detect-project.sh`