Feature/printer search filter (#920)

* feat(printers): add live search/filter bar to printers page

Adds a search bar below the page title that filters the printer list
in real time by name, model, location, and serial number. Includes an
X button to clear the search and an empty-state message when no
printers match. Filtering is purely client-side — no backend changes
needed.

Closes #852

test_backend.sh

@@ -1,11 +0,0 @@
-#!/bin/sh
-
-cd backend
-ruff check && ruff format --check
-
-#if [ "$1" = "--full" ]; then
-../venv/bin/python3 -m pytest tests/ -v -n 30
-#else
-#../venv/bin/python3 -m pytest tests/ -v -n 30 --ignore=tests/unit/services/test_bambu_ftp.py
-#fi
-#cd ..