Beta 1.7.72-beta.5 - Account tickets + ticket claim fix

• Fixed ticket claim: now includes users map in response to show claimant name (was showing "unknown")
• Added backend support_ticket handler in launcher-server.js
• Enabled "My account" mode on Windows launcher (ModeSupport button)
• Added "My account" mode to Avalonia (Linux/Mac) launcher with account subjects
• Users can now submit account tickets: login trouble, lost account, name change, etc.
• Launcher UI shows support-specific title, subtitle, and step labels
• Support mode hides target field and shows account subject tiles
• Previous features from beta.4 included: image evidence support, staff protection, ticket claiming, personal canned replies