RES-1858 Switch to use mapbox for geocoding

[ngm]

1. Add configuration for Mapbox token. The Google API key is still used for the maps (which haven't yet been replaced) so that stays.
2. Switch to use the standard PHP geocoder and add a basic test..
3. For both group and event add/edit, remove use of vue-google-autocomplete and instead use the Mapbox one.

(new PR after cherry picking some files for #640 )

[sonarqubecloud]

SonarCloud Quality Gate failed.   

0 Bugs
0 Vulnerabilities
2 Security Hotspots
2 Code Smells

No Coverage information
0.6% Duplication

[sonarqubecloud]

SonarCloud Quality Gate failed.   

0 Bugs
0 Vulnerabilities
2 Security Hotspots
2 Code Smells

No Coverage information
0.6% Duplication

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[edwh]

Rebuilt this branch on current develop (it was ~1240 commits behind, from before CI was reworked, so no checks were running at all).

While rebasing this, it turned out most of the Mapbox plumbing this PR wanted had already landed on develop separately: config/geocoder.php (Mapbox + GeoPlugin chain), the geocoder-php/mapbox-provider / toin0u/geocoder-laravel packages, and MAPBOX_TOKEN in .env/CircleCI/Fly secrets are all already there and already used for reverse geocoding in App\Console\Commands\SetPlaceNetworkData.

So the only remaining piece of this PR's intent was the forward geocode path, App\Helpers\Geocoder::geocode() (used by group/event/user location editing), which was still calling the Google Maps HTTP API directly. That's now switched to app('geocoder'), the same Mapbox-then-GeoPlugin chain, matching the pattern already used by SetPlaceNetworkData. country_code is now taken directly from the provider's ISO country code rather than matching the country name against our own list. The unused reverseGeocode() method is removed (nothing calls it any more; reverse geocoding goes through SetPlaceNetworkData's direct reverseQuery() call). The public interface, container binding, and existing test mocks (GeocoderMock, GeocoderFailMock) are unchanged, and tests/Unit/GeocoderTest.php on develop already expects exactly this interface, so no other files needed changes.

Infra/build files (Dockerfile, docker-compose.yml, docker_run.sh, package.json/package-lock.json) are taken as-is from develop - the versions in this branch were three years stale and would only have caused conflicts.

Not carried over: the third part of the original PR description - replacing vue-google-autocomplete with a Mapbox GL JS geocoder widget in GroupLocation.vue/VenueAddress.vue. Those two components have been substantially reworked on develop since this branch was created (a shared PlacesAutocomplete.vue wrapper, Leaflet-based map display, and Playwright-testability watchers that are specifically built around the current Google Autocomplete widget's DOM behaviour). Redoing that swap properly is a real frontend rewrite in its own right, not a rebase, and risks breaking the existing Playwright coverage for group/event location editing. Recommend splitting that into its own follow-up PR if it's still wanted, rather than bundling it here.

Needs manual verification:

• A live Mapbox geocode against a real MAPBOX_TOKEN - CI should exercise this via tests/Unit/GeocoderTest.php (the CircleCI secret should be a real token; local dev's .env only has the placeholder 1234).
• That the production/Fly MAPBOX_TOKEN secret is actually set (docs say it should be, as a shared secret, but worth double-checking before this merges).

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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