fix(windows): install Claude Code hook shims as .cmd wrappers

[jseramn]

Summary

• On Windows, Cursor and Claude Code spawn hook commands without a shell. Extensionless bash shims in ~/.claude/hooks/ trigger the "Open with" dialog and block workflows (especially on every Grep/Glob PreToolUse hook).
• Install .cmd wrappers on Windows and wire settings.json to the absolute .cmd path so CreateProcess can execute hooks directly.
• Add tests/windows/test_hook_scripts.py regression test and enable smoke-test coverage for Windows (previously skipped).

Root cause

cbm_install_hook_gate_script() always wrote #!/usr/bin/env bash scripts without a file extension. Windows has no default handler for extensionless files, so the OS prompts the user to pick an app. The smoke test explicitly skipped Windows (MINGW64_NT), so CI never caught this.

Test plan

• python tests/windows/test_hook_scripts.py <binary> fails on current release, passes with this patch
• CI smoke on windows-latest
• Manual: install on Windows, run Grep in Cursor — no "Open with" dialog

Notes

Existing Unix installs are unchanged. Re-running codebase-memory-mcp install -y on Windows migrates settings to the .cmd path.

[DeusData]

Thanks for the Windows hook-shim fix. Triage: high-priority Windows/editor integration bug.

Review will check that Windows gets executable .cmd wrappers wired by absolute path, Unix installs stay unchanged, and smoke coverage really exercises the Windows hook path that previously skipped. This is a sharp fix for #929.