Merge spike/claude-code-integration: PTY-based Claude Code with multi-agent support

Spike proved: spawning claude -p in a PTY from Rust gets Max subscription
billing. Multi-agent concurrency confirmed with session resumption.
Includes AgentPool REST API, claude-code provider, and spike documentation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

# Conflicts:
#	.ignore

frontend/vite.config.ts

@@ -5,6 +5,7 @@ import { defineConfig } from "vite";
 export default defineConfig(() => ({
   plugins: [react()],
   server: {
+    port: 5173,
     proxy: {
       "/api": {
         target: "http://127.0.0.1:3001",