Feature/gpx export optimisations

[nagisml]

• Introduction of Settings on GPX Exports
• Option for Corrected/Original Coords Export caches to a GPX file WITHOUT corrected coordinates #596
• Record limits Add Flexibility in GPX/GGZ Creation - Records to Export #774

[AgreeDK]

@nagisml
Thanks, this looks really good! 👍

I've tested it locally, both on its own and merged on top of beta together with #947 and #949: the full unit suite passes (4410 tests) and mypy is clean.

What I like:

• FileExportSettings.from_dict() falls back to defaults for missing or invalid keys, so saved settings keep loading when new options are added later. Nicely thought through.
• The e2e fix uses the existing wait_for_refresh() helper from tests/data.py. That's the right approach, see below.

One observation, not a blocker: the new options (corrected coords on/off, max records) are only in the file export dialog, not in Send to GPS (gps_dialog.py). That's fine as scope for this PR, but users will probably ask for the same options there, so it might be worth a follow-up issue.

Merge order: all three of your open PRs (#947, #948, #949) change the same flaky test in tests/e2e-tests/test_e2e_filter.py, each in a slightly different way, so only the first one merges cleanly. Since this PR's version is the best one (it reuses wait_for_refresh()), I plan to merge this one first. I'll comment on the other two.