feat(cloud): make org invites shareable via HTTPS deep-link handoff

[beruro]

Problem

Custom-scheme organization invite links are awkward to share through Slack and social surfaces, and a second application instance may not forward deep links safely to the running ORG2 process.

Solution

• Generate HTTPS handoff links while keeping the invite capability in the URL fragment.
• Preserve direct orgii://cloud/join and legacy HTTPS query-link compatibility while rejecting foreign URLs.
• Enable single-instance deep-link forwarding and restore or recreate the main window without logging capability-bearing argv.
• Preserve the current develop two-card invite UI while updating it to HTTPS handoff semantics.
• Validation: 71 focused Vitest tests, TypeScript typecheck, targeted ESLint, Rust check/rustfmt, diff check, handoff-site tests, and manual second-account acceptance.

Potential risks

• The deployed HTTPS handoff site is an external runtime dependency: https://orgii-invite-link.atah2000.chatgpt.site/
• Platform-specific single-instance and deep-link behavior still needs release-bundle coverage on macOS, Windows, and Linux.
• Invite capabilities must never be logged or moved from the URL fragment into server-visible request data.

[Harry19081]

@Neonforge98 Can you investigate how to deploy this?