[Feature]: Support Antigravity Accounts in a client-selected WSL distro #25847

Problem or use case

I use Orca on Windows with the WSL distro Ubuntu-24.04. Antigravity CLI (agy) is already signed in inside that distro, but Orca's Antigravity Accounts card displays:

Antigravity account management for a client-selected WSL distro is not supported yet. Use agy inside that distro; the host account was not changed.

This prevents me from viewing and managing the existing WSL account through Orca's Accounts interface.

Steps to reproduce:

1. Sign in to agy inside the WSL distro Ubuntu-24.04.
2. Configure Orca to use that WSL distro.
3. Open AI Provider Accounts and view the Antigravity card for that environment.
4. Observe the unsupported-distro error despite the CLI already being signed in.

Proposed solution

Support Antigravity account operations for the WSL distro selected in Orca:

• Detect and display the existing signed-in account, independently of whether quota retrieval succeeds.
• Allow saving and selecting account profiles using the selected distro's actual credential storage.
• Keep operations scoped to that distro, without changing the Windows host account or another distro's credentials.
• Verify that newly launched Antigravity sessions use the selected account. Existing sessions may retain their previous account.

Reuse the native account-management infrastructure introduced by #24691 where applicable, with a verified adapter for the selected WSL distro.

Alternatives or additional context

Signing in and managing authentication directly inside WSL remains the workaround, but it does not provide account management through Orca's Accounts interface.

PR #24691 added native Antigravity Accounts but explicitly excluded client-selected WSL operations. This request covers that remaining platform limitation.

PR #23761 also proposes multi-account support and includes WSL selection fields. However, at the inspected head (8dcf3e2e5553f64c55c31a37005758955eab657d), its credential-storage implementation ignores the requested target and returns managedAuthRuntime: 'host' with wslDistro: null. This request specifically concerns actual credential operations inside the selected WSL distro.

Related:

• Add verified native Antigravity Accounts on the owning runtime #24691 — Add verified native Antigravity Accounts on the owning runtime
• feat: add Antigravity multi-account support #23761 — Add Antigravity multi-account support
• [Feature]: Show Antigravity CLI sign-in and usage in Accounts #19587 — Show Antigravity CLI sign-in and usage in Accounts
• Migrate Gemini CLI provider integration to Antigravity with multi-account support #17345 — Migrate Gemini CLI provider integration to Antigravity with multi-account support