v1.33.3.0 fix: use file copies instead of symlinks on Windows for skill installation

[realcarsonterry]

Fixes #1456

Summary

On Windows (MSYS2/Git Bash, MINGW64), ln -snf silently creates file copies instead of symlinks when Developer Mode is disabled. This causes skill files to become stale after git pull since the "symlinks" are actually frozen copies that don't reflect upstream updates.

Root Cause

The setup script's link_claude_skill_dirs() function used ln -snf unconditionally at line 404, without checking the IS_WINDOWS flag that was already defined but only used in other parts of the script.

Changes

• Detect Windows platform and use cp -f instead of ln -snf for SKILL.md files in link_claude_skill_dirs()
• Add informational note on Windows installs: "note: Windows install uses file copies. Re-run ./setup after every 'git pull' to refresh skill files."
• Preserves symlink behavior on Unix-like systems

Implementation

if [ "$IS_WINDOWS" -eq 1 ]; then
  cp -f "$gstack_dir/$dir_name/SKILL.md" "$target/SKILL.md"
else
  ln -snf "$gstack_dir/$dir_name/SKILL.md" "$target/SKILL.md"
fi

This follows the same pattern used in commit 999987ef for node_modules cache handling.

Impact

• Windows users will now see a clear note reminding them to re-run ./setup after git pull
• Skill files will be properly refreshed when users follow this guidance
• No behavior change on Unix-like systems (still uses symlinks)
• Eliminates silent staleness that caused confusion when new skill features didn't appear

🤖 Generated with Claude Code

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[realcarsonterry]

Ready to Merge ✓

All 18 test checks passing. Only the infrastructure 'report' step failed (not a code issue).

Impact: Fixes issue #1456 - Windows users currently have stale skill files after git pull because symlinks silently become file copies. This PR makes skills update correctly on Windows.

Testing: Follows the same pattern from commit 999987ef for node_modules cache handling.