Select the installed language pack when launching MoonWell

Pass WOW_LOCALE=auto alongside the selected Data directory so inherited locale
settings cannot override an installed ruRU pack. Keep language archives in the
regular manifest download and verification flow. Document the contract and
prepare launcher version 1.0.7+10 for the localization release.

Verified on Windows through FVM: full format check and flutter analyze passed;
all 76 Flutter tests passed, including manifest retention and verification of
Russian archives and the game's child environment. No macOS build was run.

docs/launcher_web_api_spec.md

@@ -286,6 +286,8 @@ When the user presses `Play`:
    - `WOW_HOST=<auth-address>`
    - `WOW_DATA=<absolute-data-directory>`
    - `BENILLA_HOME=<install-root>/benilla-config`
+   - `WOW_LOCALE=auto` (select the installed `Data/ruRU` or `WoW/Data/ruRU` language pack,
+     otherwise English; override any locale inherited from the launcher's parent)
 6. launcher retains a process handle; while the process is alive, it disables repeated game launches
    and client synchronization
 7. when the process exits, the launcher returns to the ready-to-play state
@@ -297,6 +299,10 @@ If the executable, data directory, or auth endpoint is missing or invalid,
 launch fails with an error. A consumed ticket cannot authenticate again; close
 the client and press Play for a fresh ticket after a session ends.
 
+Language archives are ordinary client-manifest entries, including their nested paths,
+sizes and SHA-256 hashes. Synchronization verifies and retains required `ruRU` files
+and removes obsolete archives under the same manifest-authoritative Data policy.
+
 ## Error Behavior
 
 The launcher surfaces errors for: