Fix sx-browser.js cache bust: use correct path for hash computation

_script_hash used relative Path("static") which resolved to /app/static/
inside the container, but the file is at /app/shared/static/. Use
Path(__file__).parent.parent to resolve from shared/ correctly.

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

shared/sx/helpers.py

@@ -1047,7 +1047,7 @@ def _script_hash(filename: str) -> str:
     """Compute MD5 hash of a static script file, cached for process lifetime."""
     if filename not in _SCRIPT_HASH_CACHE:
         try:
-            data = (Path("static") / "scripts" / filename).read_bytes()
+            data = (Path(__file__).resolve().parent.parent / "static" / "scripts" / filename).read_bytes()
             _SCRIPT_HASH_CACHE[filename] = hashlib.md5(data).hexdigest()[:8]
         except OSError:
             _SCRIPT_HASH_CACHE[filename] = "dev"