Add demo for Ray.Compiler usage

Create a working demo showing Ray.Compiler's two-phase architecture:
compile-time dependency resolution and runtime script execution.

Demo structure:
- demo/GreeterInterface.php - Service interface
- demo/Greeter.php - Service implementation
- demo/AppModule.php - Ray.Di module with bindings
- demo/compile.php - Compilation script (build time)
- demo/run.php - Execution script (runtime)
- demo/README.md - Comprehensive documentation

Key features demonstrated:
1. Compile bindings into optimized PHP scripts
2. Use CompiledInjector for zero-overhead DI at runtime
3. Generated scripts are simple: new Class() + return
4. No reflection or dependency resolution in production

Usage:
```bash
php demo/compile.php  # Generate scripts
php demo/run.php      # Execute with compiled DI
```

Changes:
- Add demo/ directory with example files
- Update composer.json autoload-dev for demo namespace
- Add demo/.compiled to .gitignore

All tests pass ✓

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: koriym

.gitignore

@@ -10,3 +10,4 @@ build
 /coverage.xml
 *.bak
 .claude
+/demo/.compiled

composer.json

@@ -39,6 +39,7 @@
     "autoload-dev": {
         "psr-4": {
             "Ray\\Compiler\\": ["tests", "tests/Fake"],
+            "Ray\\Compiler\\Demo\\": "demo",
             "Ray\\Di\\": "tests/Fake/Assisted"
         },
         "files": ["tests/deleteFiles.php"]

demo/AppModule.php

@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Ray\Compiler\Demo;
+
+use Ray\Di\AbstractModule;
+
+final class AppModule extends AbstractModule
+{
+    protected function configure(): void
+    {
+        $this->bind(GreeterInterface::class)->to(Greeter::class);
+    }
+}

demo/Greeter.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Ray\Compiler\Demo;
+
+final class Greeter implements GreeterInterface
+{
+    public function __construct(private readonly string $greeting = 'Hello')
+    {
+    }
+
+    public function greet(string $name): string
+    {
+        return sprintf('%s, %s!', $this->greeting, $name);
+    }
+}

demo/GreeterInterface.php

@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Ray\Compiler\Demo;
+
+interface GreeterInterface
+{
+    public function greet(string $name): string;
+}

demo/README.md

@@ -0,0 +1,98 @@
+# Ray.Compiler Demo
+
+This demo shows how Ray.Compiler pre-compiles dependency injection bindings into executable PHP scripts.
+
+## Architecture
+
+Ray.Compiler uses a **two-phase architecture**:
+
+### Compile-time (Development/Build)
+- Uses Ray.Di's full dependency resolution
+- Analyzes bindings, constructs dependency graph
+- Generates optimized PHP scripts
+
+### Runtime (Production)
+- Uses minimal `CompiledInjector`
+- Executes pre-compiled scripts
+- **No reflection, no dependency resolution**
+
+## Files
+
+- `GreeterInterface.php` - Service interface
+- `Greeter.php` - Service implementation
+- `AppModule.php` - Dependency injection bindings
+- `compile.php` - Compilation script (run at build time)
+- `run.php` - Execution script (uses compiled scripts)
+
+## Usage
+
+### Step 1: Compile (Build Time)
+
+```bash
+php demo/compile.php
+```
+
+This generates optimized PHP scripts in `demo/.compiled/`:
+- `Ray_Compiler_Demo_GreeterInterface-.php`
+- Other dependency scripts
+
+### Step 2: Run (Runtime)
+
+```bash
+php demo/run.php
+```
+
+Output:
+```
+Hello, World!
+Hello, Ray.Compiler!
+
+✓ Using pre-compiled dependency injection!
+✓ No reflection, no dependency resolution at runtime
+✓ Check demo/.compiled/ for generated PHP scripts
+```
+
+## Inspecting Generated Code
+
+After compilation, check the generated scripts:
+
+```bash
+cat demo/.compiled/Ray_Compiler_Demo_GreeterInterface-.php
+```
+
+You'll see plain PHP code that instantiates objects - no complex DI logic!
+
+## Benefits
+
+1. **Performance**: No runtime reflection or dependency resolution
+2. **Zero Overhead**: Compiled scripts are simple `new` and `return` statements
+3. **Debuggable**: Generated code is readable PHP
+4. **Production Ready**: No heavy DI framework in production
+
+## How It Works
+
+```
+┌─────────────────┐         ┌──────────────┐
+│  Ray.Di Module  │────────▶│   Compiler   │
+│  (Bindings)     │         │              │
+└─────────────────┘         └──────┬───────┘
+                                   │
+                                   ▼
+                            ┌──────────────┐
+                            │  PHP Scripts │
+                            │ (Optimized)  │
+                            └──────┬───────┘
+                                   │
+                                   ▼
+                            ┌──────────────────┐
+                            │ CompiledInjector │
+                            │  (Lightweight)   │
+                            └──────────────────┘
+```
+
+## Next Steps
+
+- Add more complex dependencies (interfaces, providers, AOP)
+- Try scopes (singleton vs prototype)
+- Explore assisted injection
+- Use with your real application modules

demo/compile.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+use Ray\Compiler\Compiler;
+use Ray\Compiler\Demo\AppModule;
+
+require dirname(__DIR__) . '/vendor/autoload.php';
+
+$scriptDir = __DIR__ . '/.compiled';
+$module = new AppModule();
+
+// Compile the dependency injection container
+$compiler = new Compiler();
+$compiler->compile($module, $scriptDir);
+
+echo "✓ Compilation complete! Scripts saved to: {$scriptDir}\n";
+echo "✓ Run 'php demo/run.php' to execute the compiled application\n";

demo/run.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+use Ray\Compiler\CompiledInjector;
+use Ray\Compiler\Demo\GreeterInterface;
+
+require dirname(__DIR__) . '/vendor/autoload.php';
+
+$scriptDir = __DIR__ . '/.compiled';
+
+// Use the compiled injector (no Ray.Di runtime overhead)
+$injector = new CompiledInjector($scriptDir);
+
+/** @var GreeterInterface $greeter */
+$greeter = $injector->getInstance(GreeterInterface::class);
+
+echo $greeter->greet('World') . "\n";
+echo $greeter->greet('Ray.Compiler') . "\n";
+
+echo "\n";
+echo "✓ Using pre-compiled dependency injection!\n";
+echo "✓ No reflection, no dependency resolution at runtime\n";
+echo "✓ Check {$scriptDir}/ for generated PHP scripts\n";