Implement complete InferenceProvider system with OpenRouter integration

## Features
- 🔧 InferenceProvider interface with pluggable architecture
- 🔑 OpenRouter API key and OAuth PKCE authentication providers
- 🛠️ Tool calling support with automatic agent loop execution
- 📱 Interactive test UI with model selection and chat interface
- 🎯 Provider-level filtering to tool-capable models only
- ⚛️ React context with proper state management for UI reactivity

## Components
- Core types and interfaces in src/types/inference.ts
- OpenRouter client with shared utilities for both auth methods
- Two separate providers (composition over inheritance):
  - OpenRouterApiProvider for API key authentication
  - OpenRouterOAuthProvider for OAuth PKCE flow
- React InferenceContext with useInference hook
- Interactive test UI with tool calling demonstration
- OAuth callback routing with proper namespacing

## Tool Calling
- 3 test tools: weather, calculator, time
- Automatic tool execution and agent loop
- Visual tool call display with arguments and results
- Error handling for malformed tool calls

## Bug Fixes
- Fixed model selection UI reactivity issue
- Fixed OAuth popup race condition causing "cancelled" errors
- Proper cleanup of event listeners and intervals

## Documentation
- Comprehensive interface design document
- Implementation strategy and key design decisions
- Testing approach and security considerations

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

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

vite.config.ts

@@ -0,0 +1,23 @@
+import { defineConfig } from 'vite'
+import react from '@vitejs/plugin-react'
+import path from 'path'
+
+// https://vitejs.dev/config/
+export default defineConfig({
+  plugins: [react()],
+  resolve: {
+    alias: {
+      '@': path.resolve(__dirname, './src'),
+    },
+  },
+  define: {
+    global: 'globalThis',
+  },
+  server: {
+    port: 3000,
+  },
+  build: {
+    outDir: 'dist',
+    sourcemap: true,
+  },
+})