v0.3.1 - Document plugin installation bug

Changes

• Remove local development installation section due to UserPromptSubmit hook bug
• Add note about plugin installation not working with link to #10225
• Manual installation via settings.json is the only working method until upstream bug is fixed

Bug Details

UserPromptSubmit hooks from plugins are matched but never execute in Claude Code 2.0.24. See anthropics/claude-code#10225 for details.

Installation

Use manual installation method documented in README:

cp scripts/improve-prompt.py ~/.claude/hooks/
chmod +x ~/.claude/hooks/improve-prompt.py

Then update ~/.claude/settings.json with the hook configuration.