Add AOT compilation support for Glojure standard library

[jfhamlin]

This commit introduces Ahead-Of-Time (AOT) compilation specifically for the Glojure standard library, significantly improving startup performance by pre-compiling core modules to Go code.

Key Features:

• Code generation infrastructure in pkg/runtime/codegen.go
• Pre-compiled standard library modules (core, core_print, protocols, etc.)
• Automatic AOT compilation during build via 'make generate'
• Runtime registration and loading of pre-compiled namespaces
• Comprehensive test suite with golden file testing

Implementation Scope (Standard Library Only):

• This initial implementation focuses exclusively on pre-compiling the Glojure standard library for faster startup
• User code AOT compilation will be added in future updates
• Pre-compiled modules are embedded in the binary at build time

Technical Implementation:

• AST-to-Go code transformation with proper scoping
• Support for all core language constructs used in stdlib
• Special forms: def, set!, case, letfn, try/catch/finally, etc.
• Metadata preservation and symbol/keyword pre-allocation
• Topological sorting for dependency resolution

Performance Benefits:

• Eliminates parse and eval overhead for standard library at runtime
• REPL startup time significantly reduced
• Default enabled. Disable with GLOJURE_USE_AOT=false environment variable