Changes

PR #1802 by nickarino: fix: improve template extension handling for {{input}} and add examples

• Fix: improve template extension handling for {{input}} and add examples
• Extract InputSentinel constant to shared constants.go file and remove duplicate inputSentinel definitions from template.go and patterns.go
• Create withTestExtension helper function to reduce test code duplication and refactor 3 test functions to use the helper
• Fix shell script to use $@ instead of $- for proper argument quoting
• Add prominent warning at top of Extensions guide with visual indicators and update main README with brief Extensions section

PR #1823 by ksylvan: Add missing patterns and renumber pattern explanations list

• Add apply_ul_tags pattern for content categorization
• Add extract_mcp_servers pattern for MCP server identification
• Add generate_code_rules pattern for AI coding guardrails
• Add t_check_dunning_kruger pattern for competence assessment
• Renumber all patterns from 37-226 to 37-230 and insert new patterns at positions 37, 129, 153, 203