fix(proxy): prevent "container name already in use" error during proxy restart

Add wait loops to ensure containers are fully removed before restarting.
This fixes race conditions where docker compose would fail because an
existing container was still being cleaned up.

Changes:
- StartProxy: Add explicit stop, wait loop before docker compose up
- StopProxy: Add wait loop after container removal
- Both actions now poll up to 10 seconds for complete removal
- Add error suppression to handle non-existent containers gracefully

Tests:
- Add StartProxyTest.php with 3 tests for cleanup logic
- Add StopProxyTest.php with 4 tests for stop behavior

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

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

app/Actions/Proxy/StopProxy.php

@@ -24,8 +24,15 @@ class StopProxy
             }
 
             instant_remote_process(command: [
-                "docker stop --time=$timeout $containerName",
-                "docker rm -f $containerName",
+                "docker stop --time=$timeout $containerName 2>/dev/null || true",
+                "docker rm -f $containerName 2>/dev/null || true",
+                '# Wait for container to be fully removed',
+                'for i in {1..10}; do',
+                "    if ! docker ps -a --format \"{{.Names}}\" | grep -q \"^$containerName$\"; then",
+                '        break',
+                '    fi',
+                '    sleep 1',
+                'done',
             ], server: $server, throwError: false);
 
             $server->proxy->force_stop = $forceStop;