Implement Python → LLVM IR → WASM reactive framework

MAJOR ACHIEVEMENT: Full working reactive framework!

## What's Working

✅ Python → AST → Ritz IR → LLVM IR → WASM pipeline
✅ Reactive signals stored in WASM memory (@signal_name = global i32)
✅ Event handlers exported from WASM and callable from JS
✅ Clean runtime with RitzLoader and debug tools
✅ Two working examples: HelloWorld and HighFive counter

## Core Components

### Parser (ritz/parser.py)
- Uses Python's ast module to parse components
- Handles @component decorator, signals, event handlers
- Supports yield, with statements, f-strings, augmented assignment (+=)
- Clean syntax: from ritz.syntax import *

### LLVM IR Code Generator (ritz/llvm_codegen_signals.py)
- Generates LLVM IR directly (not C!)
- Signals as global variables in WASM memory
- Exports getter/setter functions for each signal
- Exports event handler functions for JS to call
- UTF-8 string handling

### Build System (ritz/build.py)
- Python → AST → IR → LLVM IR → clang --target=wasm32 → WASM
- Saves intermediate .ll files for inspection
- Debug symbols support (-g flag)

### Runtime (runtime/ritz-runtime.js)
- RitzRuntime class: DOM bridge for WASM
- RitzLoader class: Simplified component loading
- Debug bar with Ctrl+` toggle
- Signal updates trigger DOM updates

## Examples

### HelloWorld.py
Simple static content - renders <p>Hello World</p>

### HighFive.py
Reactive counter with:
- Signal in WASM memory (high_fives = signal(0))
- Event handler (increment function)
- DOM updates on signal change

## Test Coverage

- 4 parser tests (all passing)
- 4 LLVM codegen tests (all passing)
- 4 signal parsing tests (all passing)
- Code formatted with black and ruff

## Next Steps

- <script type="text/ritz"> in-browser compilation
- Better signal-to-DOM binding tracking
- More complex examples (TodoMVC, forms, lists)
- Playwright browser tests

---

This is a genuinely innovative framework: write Python, compile to WASM,
run with reactive signals in WASM memory. No virtual DOM, no transpilation,
just compiled Python with fine-grained reactivity.

🎉 Python → WASM → Reactive UI is REAL!

ritz/syntax.py

@@ -0,0 +1,179 @@
+"""
+Ritz syntax placeholders for writing components.
+
+These are runtime placeholders that allow components to be valid Python.
+The compiler ignores imports and uses AST parsing instead.
+"""
+
+
+def component(func):
+    """Component decorator - marks a function as a Ritz component."""
+    return func
+
+
+def signal(initial_value):
+    """Create a reactive signal with an initial value."""
+    pass
+
+
+# HTML Elements - Context managers for building DOM
+class _Element:
+    """Base element class."""
+
+    def __init__(self, *children, **props):
+        self.children = children
+        self.props = props
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, *args):
+        pass
+
+
+# Standard HTML elements
+class Div(_Element):
+    """<div> element."""
+
+    pass
+
+
+class P(_Element):
+    """<p> element."""
+
+    pass
+
+
+class Button(_Element):
+    """<button> element."""
+
+    pass
+
+
+class Span(_Element):
+    """<span> element."""
+
+    pass
+
+
+class H1(_Element):
+    """<h1> element."""
+
+    pass
+
+
+class H2(_Element):
+    """<h2> element."""
+
+    pass
+
+
+class H3(_Element):
+    """<h3> element."""
+
+    pass
+
+
+class Label(_Element):
+    """<label> element."""
+
+    pass
+
+
+class Input(_Element):
+    """<input> element."""
+
+    pass
+
+
+class Form(_Element):
+    """<form> element."""
+
+    pass
+
+
+class Section(_Element):
+    """<section> element."""
+
+    pass
+
+
+class Article(_Element):
+    """<article> element."""
+
+    pass
+
+
+class Header(_Element):
+    """<header> element."""
+
+    pass
+
+
+class Footer(_Element):
+    """<footer> element."""
+
+    pass
+
+
+class Nav(_Element):
+    """<nav> element."""
+
+    pass
+
+
+class Ul(_Element):
+    """<ul> element."""
+
+    pass
+
+
+class Ol(_Element):
+    """<ol> element."""
+
+    pass
+
+
+class Li(_Element):
+    """<li> element."""
+
+    pass
+
+
+class A(_Element):
+    """<a> element."""
+
+    pass
+
+
+class Img(_Element):
+    """<img> element."""
+
+    pass
+
+
+# Export all for convenience
+__all__ = [
+    "component",
+    "signal",
+    "Div",
+    "P",
+    "Button",
+    "Span",
+    "H1",
+    "H2",
+    "H3",
+    "Label",
+    "Input",
+    "Form",
+    "Section",
+    "Article",
+    "Header",
+    "Footer",
+    "Nav",
+    "Ul",
+    "Ol",
+    "Li",
+    "A",
+    "Img",
+]