fix(lua.core): server loses pending response on concurrent request

[S1M0N38]

Ref: PR #190

Description

When a long-running request (like play) is in progress and a second request is sent before it completes, the first request's response is lost. The client receives 0 bytes for the first request while the second request's response arrives normally.

Steps to Reproduce

1. Start a run and select a blind
2. Send play({"cards": [0,1,2,3,4]})
3. 100ms later, send gamestate({}) before play has finished
4. The play response is lost (empty), while the gamestate response arrives correctly

A reproduction script is provided (script.py).

Expected Behavior

The server should either:

• Queue the second request and respond after the first completes, OR
• Reject the second request with a 503 "Service Unavailable" error

In no case should a response be silently lost.

Actual Behavior

The play response is 0 bytes. The response body is completely missing — the server closes the first connection without writing the pending response.

Environment

• OS: macOS
• Lovely version: 0.8.0
• SMODS version: v1.0.0~BETA-1221a
• BalatroBot commit: 084044e

Files

• 60065.log
• 60065.req.jsonl.txt
• 60065.res.jsonl.txt
• script.py