feat: project detection heuristics for CLAUDE.md generation

[futuregerald]

Summary

• Adds detect.go with ProjectInfo struct and detectors for Go, Node.js (React, Next.js, AdonisJS, Svelte, Express), Rust, Python, Ruby, and PHP projects
• detectProject(dir) reads project files (package.json, go.mod, Cargo.toml, etc.) to extract name, description, framework, and commands
• applyProjectDetection() replaces {{...}} template placeholders with real values, inserts language-specific template snippets, strips unfilled placeholders, and removes empty sections
• Updates generateConfigFile and generateFrameworkConfig in main.go to use detection for all targets (Claude Code, Cursor, Copilot, etc.)

Test Plan

• 14 unit tests covering all detectors, template processing, placeholder stripping, empty section removal
• Table-driven tests for Node.js framework detection priority (AdonisJS > Svelte > Next.js > React > Express > fallback)
• Integration test with fstest.MapFS verifying full template processing pipeline
• Manual verification: Go project detection, empty dir fallback, non-Claude target, dry-run output
• Code review: 1 Critical + 6 Important findings addressed
• Code simplifier: 6 recommendations applied

🤖 Generated with Claude Code