Hand Flarial access tokens to API v2 beta DLLs

[aShanki]

The API v2 beta DLL needs a Flarial access token from the launcher to activate its personalized build. Add that handoff to the experimental FlarialClientBeta runtime path; refresh credentials remain in the launcher.

• Create a current-user-only named pipe before injection and verify the connecting game PID. Send a length-prefixed access token with a 30-second deadline; cancel and clean up on failure.
• Refresh before download/injection and require the same account. Download fresh activation material for each launch, reject redirects, limit the DLL to 32 MiB, verify SHA-256 and the full commit export, and replace the destination only after validation.
• Preserve release injection behavior. This targets the existing experimental runtime API; it does not switch the legacy UI's Discord account/client wiring.

Validation: Flarial.Runtime and the standalone handoff test project compile under .NET 10 with zero warnings/errors. Windows CI exercises successful delivery, wrong-PID rejection, cancellation and token length limits. Requires dll-css #1005. Real game injection, packaged/AppContainer IPC, and a production personalized download-to-activation run remain unverified; keep draft until those pass. A successful Launch result confirms injection and token delivery, not a server activation acknowledgment.

Latest checks: Validation: Windows .NET runtime build and sender integration tests passed (run); local .NET builds also passed with zero warnings/errors.

[Aetopia]

Use WinRT's PasswordVault for tokens.