Switch to Gradio 5.x — no SSR, no Node.js required

Gradio 6 SSR build hangs on HF Spaces regardless of config.
Gradio 5 is stable, no SSR, compatible API. Remove all SSR
workarounds. Docker SDK + slim image + Gradio 5.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -1,14 +1,12 @@
 FROM python:3.12-slim
 
-RUN apt-get update && apt-get install -y git curl && rm -rf /var/lib/apt/lists/*
-RUN curl -fsSL https://deb.nodesource.com/setup_20.x | bash - && \
-    apt-get install -y nodejs && rm -rf /var/lib/apt/lists/*
+RUN apt-get update && apt-get install -y git && rm -rf /var/lib/apt/lists/*
 
 RUN useradd -m -u 1000 user
 WORKDIR /app
 
 COPY requirements.txt .
-RUN pip install --no-cache-dir -r requirements.txt gradio==6.10.0
+RUN pip install --no-cache-dir -r requirements.txt "gradio>=5.12,<6"
 
 COPY . .
 

app.py

@@ -5,10 +5,8 @@ Pre-loaded workspace, global daily question limit, themed to match appsimple.io.
 
 from __future__ import annotations
 
-import os
-os.environ["GRADIO_SSR_MODE"] = "false"
-
 import json
+import os
 import re
 import tempfile
 import time
@@ -511,7 +509,7 @@ def build_app() -> gr.Blocks:
             height=None,
             label="",
             show_label=False,
-            buttons=[],
+            show_copy_button=False,
             elem_id="chat-output",
         )