Adding commands to the compiler.

[FernandoTheDev]

This commit adds a command system to the Cx compiler (cx <command>) and makes several other changes. Summary:

New CLI commands

• cx build — scaffolds a new Cx project (generates src/main.cx and cx.json), implemented in the new src/builder.d.
• cx compile — compiles an existing Cx project by reading its cx.json.
• cx run — compiles and then runs the project.
• Major refactor of main.d: the compilation logic was extracted into a reusable compile() function that takes a CXArgs struct (previously everything lived inline in main), allowing compile/run/direct .cx file usage to share the same code path.
• New --gcc flag to force GCC as the C compiler, and the auto-detection order for the C compiler now prefers tcc → gcc → cc.

Language/compiler (codegen & parser)

• Enums now generate a _ids array in the emitted C code (Foo_ids[]) mapping each variant to its name as a string, and support was added for enum.id syntax to get the enum variant's name at runtime (used to replace manual functions like opCodeToStr).
• Arrow functions (=> expr) now require a trailing ; (fixed across several examples and the standard library where the semicolon was missing).
• Small indentation fix in a generated foreach loop.
• Type resolver now propagates the left-hand side's type as a "reference" type when resolving the right-hand side of binary expressions.
• In the VM example, a return was changed to continue in the "Print" opcode case.

New examples

• examples/kernel/: a small bare-metal x86 kernel written in Cx (assembly bootloader, entry trampoline, linker script, Makefile, and a kernel.cx that draws a text-mode VGA interface).
• examples/windows/langtoy.cx: a toy language interpreter (lexer + parser + expression evaluator supporting let, print, assignments) written in Cx.
• examples/windows/main.cx: a simple example with addition and pointers.
• examples/enum2.cx and examples/dot_anon4.cx: new examples testing enums and nested anonymous initializers.

Other

• .gitignore now ignores *.o, *.bin, *.img (build artifacts from the kernel example).
• Compiler version bumped from 0.2.1 to 0.2.2.
• The unit test runner (tests/unit.d) now wraps to!int in try/catch instead of letting the exception propagate.