Account Display Names

What changed: OAuth account display names are now captured and synchronized

How it works now:

• Display names are fetched from /api/oauth/profile endpoint
• Stored alongside email, organization, and UUID
• Automatically updated during token refresh
• Available for showing richer user identification

Details:

• Improves user identification beyond email addresses
• Kept in sync with server changes
• Evidence: Dq0() at line 405124 returns { subscriptionType, displayName } (previously JB0() at line 371316 returned only subscription string)