feat: Add agent upgrade awareness documentation and tooling

Implements bd-hwmp and bd-5otr (part of epic bd-nxgk) to help AI agents
automatically detect and adapt to bd upgrades.

## Changes

### Documentation (bd-hwmp)
- Added "After Upgrading bd" section to AGENTS.md with step-by-step workflow
- Enhanced "Pro Tips for Agents" with upgrade detection guidance
- Documents bd info --whats-new and bd hooks install commands
- References GitHub Discussion #239

### Startup Hook (bd-5otr)
- Created examples/startup-hooks/bd-version-check.sh
  - Auto-detects bd version changes via .beads/metadata.json
  - Shows bd info --whats-new when upgrade detected
  - Auto-updates outdated git hooks
  - Handles edge cases (no jq, not in beads project, etc.)
- Created examples/startup-hooks/README.md with integration examples
  - Claude Code, GitHub Copilot, Cursor integration patterns
  - Comprehensive usage and troubleshooting guide
- Updated examples/README.md with new startup-hooks section

## Impact

Agents can now:
- Automatically detect bd upgrades at session start
- See what changed without re-reading all documentation
- Keep git hooks in sync automatically
- Adapt workflows based on new features

Works today with zero bd code changes required!

Related: #239

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

examples/README.md

@@ -4,16 +4,22 @@ This directory contains examples of how to integrate bd with AI agents and workf
 
 ## Examples
 
+### Agent Integration
 - **[python-agent/](python-agent/)** - Simple Python agent that discovers ready work and completes tasks
   - **[AGENT_MAIL_EXAMPLE.md](python-agent/AGENT_MAIL_EXAMPLE.md)** - Multi-agent coordination with Agent Mail
 - **[bash-agent/](bash-agent/)** - Bash script showing the full agent workflow
+- **[startup-hooks/](startup-hooks/)** - Session startup scripts for automatic bd upgrade detection
+- **[claude-desktop-mcp/](claude-desktop-mcp/)** - MCP server for Claude Desktop integration
+- **[claude-code-skill/](claude-code-skill/)** - Claude Code skill for effective beads usage patterns
+
+### Tools & Utilities
 - **[monitor-webui/](monitor-webui/)** - Standalone web interface for real-time issue monitoring and visualization
 - **[markdown-to-jsonl/](markdown-to-jsonl/)** - Convert markdown planning docs to bd issues
 - **[github-import/](github-import/)** - Import issues from GitHub repositories
 - **[git-hooks/](git-hooks/)** - Pre-configured git hooks for automatic export/import
 <!-- REMOVED (bd-4c74): branch-merge example - collision resolution no longer needed with hash IDs -->
-- **[claude-desktop-mcp/](claude-desktop-mcp/)** - MCP server for Claude Desktop integration
-- **[claude-code-skill/](claude-code-skill/)** - Claude Code skill for effective beads usage patterns
+
+### Workflow Patterns
 - **[contributor-workflow/](contributor-workflow/)** - OSS contributor setup with separate planning repo
 - **[team-workflow/](team-workflow/)** - Team collaboration with shared repositories
 - **[multi-phase-development/](multi-phase-development/)** - Organize large projects by phases (planning, MVP, iteration, polish)