Prepare for public launch: comprehensive examples, docs, and tooling

This commit adds everything needed for a successful public launch:

**New Documentation**
- SECURITY.md: Security policy and best practices
- CLAUDE.md: Complete agent instructions for contributing to beads
- Enhanced README with pain points, FAQ, troubleshooting sections
- Added Taskwarrior to comparison table with detailed explanation

**Installation**
- install.sh: One-liner installation script with platform detection
- Auto-detects OS/arch, tries go install, falls back to building from source
- Updated README with prominent installation instructions

**Examples** (2,268+ lines of working code)
- examples/python-agent/: Full Python implementation of agent workflow
- examples/bash-agent/: Shell script agent with colorized output
- examples/git-hooks/: Pre-commit, post-merge, post-checkout hooks with installer
- examples/claude-desktop-mcp/: Documentation for future MCP server integration
- examples/README.md: Overview of all examples

**Dogfooding**
- Initialized bd in beads project itself (.beads/beads.db)
- Created issues for roadmap (MCP server, migrations, demos, 1.0 milestone)
- Exported to .beads/issues.jsonl for git versioning

**Visual Assets**
- Added screenshot showing agent using beads to README intro
- Placed in .github/images/ following GitHub conventions

This addresses all launch readiness items:
✅ Security policy
✅ Working agent examples (Python, Bash)
✅ Git hooks for automation
✅ FAQ addressing skeptics
✅ Troubleshooting common issues
✅ Easy installation
✅ Dogfooding our own tool
✅ Pain points that create urgency

Ready to ship! 🚀

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

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

examples/git-hooks/post-checkout

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+#
+# Beads post-checkout hook
+# Automatically imports JSONL to SQLite database after checking out branches
+#
+# Install: cp examples/git-hooks/post-checkout .git/hooks/post-checkout && chmod +x .git/hooks/post-checkout
+
+# Arguments provided by git:
+# $1 = ref of previous HEAD
+# $2 = ref of new HEAD
+# $3 = flag (1 if branch checkout, 0 if file checkout)
+
+# Only run on branch checkouts
+if [[ "$3" != "1" ]]; then
+    exit 0
+fi
+
+set -e
+
+# Check if bd is installed
+if ! command -v bd &> /dev/null; then
+    exit 0
+fi
+
+# Check if issues.jsonl exists
+if [[ ! -f .beads/issues.jsonl ]]; then
+    exit 0
+fi
+
+# Import issues from JSONL
+echo "🔗 Importing beads issues from JSONL..."
+
+if bd import -i .beads/issues.jsonl 2>/dev/null; then
+    echo "✓ Beads issues imported successfully"
+else
+    echo "Warning: bd import failed"
+fi
+
+exit 0