refactor(ebook-search): simplify search and phrase matching

python/ebook_search/api/web.py

@@ -3,9 +3,14 @@
 from __future__ import annotations
 
 from pathlib import Path
+from typing import TYPE_CHECKING
 
 from fastapi.templating import Jinja2Templates
 
+if TYPE_CHECKING:
+    from fastapi import Request
+    from fastapi.responses import HTMLResponse
+
 PACKAGE_DIR = Path(__file__).resolve().parent
 TEMPLATE_DIR = PACKAGE_DIR / "templates"
 STATIC_DIR = PACKAGE_DIR / "static"
@@ -21,3 +26,8 @@ def static_version(filename: str) -> int:
 
 templates = Jinja2Templates(directory=TEMPLATE_DIR)
 templates.env.globals["static_version"] = static_version
+
+
+def error_response(request: Request, message: object) -> HTMLResponse:
+    """Render the shared error partial for a failed UI request."""
+    return templates.TemplateResponse(request, "partials/error.html", {"message": str(message)}, status_code=500)