Fix #344 by downloading firmware files in a subprocess

Fix release artifact download path for actions/download-artifact@v5

Use multiprocessing.Lock instead of threading.Lock

This fixes a potential deadlock when running a server with multiple
processes.

Fix: Auto-search and select location on config page load (#280)

* Fix: Auto-search and select location on config page load

- Implements initial location search when config page loads with a pre-filled location for fields of type 'location' and 'locationbased'.
- If an exact match for the pre-filled location is found, it's selected.
- Otherwise, the first result from the location search is selected.
- For 'locationbased' fields, after the initial location is determined, options are fetched, and an attempt is made to re-select the previously configured option or the first new option.
- Ensures that the preview updates correctly upon initial load and selection.
- Fixes initialization of the location search input's text value to correctly use deviceLocation for 'locationbased' fields or field's config for 'location' fields.

Fix display of zero values

This fixes how the page displays `0` values of night_brightness,
night_start, and night_end. If any value was set to `0`, the page would
show the default values instead (i.e. `1`, `22`, and `6`, respectively).

mypy