fix: write benchmark_v5_results.json to demo/ (relative path)

Replaced the hardcoded /home/linconx/Apohara-ContextForge/demo/ output
location with os.path.dirname(__file__) so the JSON lands next to the
script in any environment — local dev, the user's /app/ container, and
the MI300X DevCloud — without further sed edits.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

demo/benchmark_v5.py

@@ -27,6 +27,7 @@ INVARIANT-13: VisualKVCache content hash is SHA256 of raw image/audio bytes.
 """
 import asyncio
 import json
+import os
 import time
 import math
 import random
@@ -1094,7 +1095,9 @@ async def main():
         ],
     }
 
-    output_path = "/home/linconx/Apohara-ContextForge/demo/benchmark_v5_results.json"
+    output_path = os.path.join(
+        os.path.dirname(os.path.abspath(__file__)), "benchmark_v5_results.json"
+    )
     with open(output_path, "w") as f:
         json.dump(output, f, indent=2)