feat: add Learning Paths, examples, and project governance files

### New Content
- Learning Paths section in README (Junior/Senior/Power User/PM tracks)
- examples/ folder with 18 ready-to-use templates:
  - 4 agents (code-reviewer, test-writer, security-auditor, refactoring)
  - 2 skills (TDD workflow, security checklist)
  - 3 commands (commit, review-pr, generate-tests)
  - 4 hooks (bash + PowerShell for security, formatting)
  - 3 config templates (settings, MCP, gitignore)
  - 2 memory templates (project + personal CLAUDE.md)

### Governance
- CHANGELOG.md: Version history (1.0.0 → 1.1.0 → Unreleased)
- CONTRIBUTING.md: Contribution guidelines for community

### Documentation
- llms.txt: Updated structure with new files/folders

This update makes the guide more actionable with concrete templates
and provides clear learning paths for different skill levels.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

examples/hooks/bash/security-check.sh

@@ -0,0 +1,47 @@
+#!/bin/bash
+# PreToolUse hook - Block commands containing secrets
+# Place in: .claude/hooks/security-check.sh
+# Register in: .claude/settings.json
+
+INPUT=$(cat)
+TOOL=$(echo "$INPUT" | jq -r '.tool_name')
+
+if [[ "$TOOL" == "Bash" ]]; then
+    COMMAND=$(echo "$INPUT" | jq -r '.tool_input.command')
+
+    # Check for common secret patterns
+    PATTERNS=(
+        "password="
+        "PASSWORD="
+        "secret="
+        "SECRET="
+        "api_key="
+        "API_KEY="
+        "apikey="
+        "token="
+        "TOKEN="
+        "aws_access_key"
+        "AWS_ACCESS_KEY"
+        "aws_secret"
+        "AWS_SECRET"
+        "private_key"
+        "PRIVATE_KEY"
+    )
+
+    for PATTERN in "${PATTERNS[@]}"; do
+        if echo "$COMMAND" | grep -qi "$PATTERN"; then
+            echo "{\"decision\": \"block\", \"reason\": \"Potential secret detected: $PATTERN\"}"
+            exit 2
+        fi
+    done
+
+    # Check for hardcoded credentials in common formats
+    # API keys (typically long alphanumeric strings)
+    if echo "$COMMAND" | grep -qE "(sk-[a-zA-Z0-9]{20,}|pk_[a-zA-Z0-9]{20,}|[a-f0-9]{32,})"; then
+        echo "{\"decision\": \"block\", \"reason\": \"Potential API key or hash detected\"}"
+        exit 2
+    fi
+fi
+
+# Allow the command
+exit 0