v0.85.1

Bug fixes

• Fix TooltipTheme.decoration so it applies to controls using ft.Tooltip(...) when the tooltip does not explicitly set decoration or bgcolor (#6432, #6482) by @ndonkoHenri.
• Fix flet-geolocator.Geolocator reliability on web and desktop: get_last_known_position() no longer crashes with TypeError: argument after ** must be a mapping, not NoneType and now returns Optional[GeolocatorPosition]; get_current_position() no longer hangs forever on web (Dart-side workaround for the upstream geolocator_web 4.1.3 inMicroseconds/inMilliseconds timeout typo) and uses sensible web defaults (time_limit: 30s, maximum_age: 5m); the previously-dropped configuration argument now actually reaches getCurrentPosition on the Dart side; the position stream is gated behind a registered on_position_change/on_error handler (with cancel-on-update to prevent leaks); and platform exceptions (LocationServiceDisabledException, PermissionDeniedException, PermissionDefinitionsNotFoundException, PermissionRequestInProgressException, PositionUpdateException, TimeoutException) are now translated into actionable error messages and surfaced to Python as RuntimeError without the default Exception: prefix (#6487) by @FeodorFitsner.
• Fix PEP 508 markers on flet's oauthlib/httpx deps not actually excluding those packages under Pyodide: the flet build web package platform has been renamed from Pyodide to Emscripten to match platform.system() inside the Pyodide runtime, and the markers now use platform_system != 'Emscripten', so the exclusion works both via flet build and a direct micropip.install("flet") in a Pyodide REPL. Requires serious_python >= 1.0.0, which is now pinned in the flet build template (#6492) by @FeodorFitsner.