fix(proxy): unset CLAUDECODE env vars before spawning CLI

Allows the proxy to spawn claude CLI even when the dev server was
started from within a Claude Code session.

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

packages/app/server/claude-proxy.ts

@@ -355,6 +355,11 @@ const server = createServer((req, res) => {
       console.log(`[proxy] → claude -p --model ${modelFlag}${webSearch ? ' [WebSearch]' : ''} "${lastUserMsg.slice(0, 60)}..."`)
 
       const procEnv = { ...process.env, NO_COLOR: '1', TERM: 'dumb' }
+      // Allow CLI to spawn even when dev server is started from inside Claude Code
+      delete procEnv.CLAUDECODE
+      delete procEnv.CLAUDE_CODE
+      delete procEnv.ANTHROPIC_CLAUDE_CODE
+      delete procEnv.CLAUDE_CODE_ENTRYPOINT
       if (webSearch === true) {
         delete procEnv.DISALLOWED_TOOLS
       }