Republish setup: fastlane + Forgejo CI, signing/version fixes, Play-policy link

- support_page: repoint comunes.org link to project page (Play re-approval)
- build.gradle: conditional release signing (debug fallback), versionCode/Name
  from pubspec, drop duplicate google-services plugin
- pubspec: version 1.10.0+10 (versionCode must exceed last uploaded)
- track AndroidManifest.xml (no secrets in it)
- fastlane: Appfile/Fastfile (deploy_play/deploy_metadata/promote_production) +
  Gemfile + es/en/gl store metadata
- .forgejo: ci.yml (analyze+test) + release.yml (tag v* -> signed AAB -> Play internal)
- README + RELEASE.md

fastlane/Appfile

@@ -0,0 +1,9 @@
+# Google Play identity + credentials for `fastlane supply`.
+#
+# The service-account JSON is injected from CI as the SUPPLY_JSON_KEY_DATA
+# secret (raw file contents) and is NEVER committed. Locally you can instead
+# export SUPPLY_JSON_KEY_DATA, or drop a gitignored play-service-account.json
+# and point json_key_file at it.
+package_name("org.comunes.fires")
+
+json_key_data_raw(ENV["SUPPLY_JSON_KEY_DATA"]) if ENV["SUPPLY_JSON_KEY_DATA"]