ProfileSwitcher was hidden when only one profile existed, making it
impossible to access "Manage Profiles" to create additional profiles.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Each profile gets its own SQLite database file for complete data isolation.
Profile selection screen at launch, sidebar switcher for quick switching,
and optional 4-6 digit PIN for privacy. Existing database becomes the
default profile with seamless upgrade.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
