Add file embedding and multi-column SQLite support

[cs01]

Summary

Language & API improvements

• SQLite: sqlite.get() and sqlite.all() now return all columns pipe-separated (e.g., "1|Alice") with a new __sqlite_row_to_string helper
• fs.statSync(): isFile and isDirectory are now methods (.isFile()) for Node.js compatibility; fixed path.join() behavior
• Compile-time file embedding: New ChadScript.embedFile(), embedDir(), and getEmbeddedFile() for bundling static assets into binaries
• fix path.resolve to join all arguments before calling realpath

Build & tooling

• Cross-compilation support for different target architectures
• argparse subcommands: Added subcommand support; migrated chad-native.ts to use it
• HTTP server: Content-type detection from file extensions (.css, .js, .json, .html, .svg, .png, .jpg, .woff2, .wasm)
• CI improvements: Added --target-cpu flag; default to x86-64 in CI to fix SIGILL on runners

Examples & other

• New Hacker News example app demonstrating embedded files and HTTP routing
• Added query and parallel example programs
• Installer updates (color escapes, linker flags for macOS SDK)

All tests pass; self-hosting verified.