otp (#41)

* Add email OTP authentication system and private room management

## Authentication System
- Implement email OTP-based authentication with User and OTPToken models
- Add auth.py module with OTP generation, email sending, and session management
- Create authentication endpoints: /auth/send-otp, /auth/verify-otp, /auth/claim-name, /auth/status, /auth/logout
- Add authentication modal UI with email verification and display name claiming
- Support SMTP configuration via environment variables (optional)

## Room Privacy & Ownership
- Add is_private, is_archived, owner_id, and forked_from_id fields to Room model
- Implement private rooms (single-user, owner-only access)
- Add room forking: users can fork public rooms to public or private
- Add room archive/delete endpoints (owner-only operations)
- Implement access control for private room viewing

## UI Improvements
- Add public/private room tabs in sidebar
- Show authentication prompt in private rooms tab for non-authenticated users
- Add room action buttons (fork, archive, delete) with proper permissions
- Update homepage with statistics (public/private rooms, active users, active rooms)
- Remove model/voice from URL query strings, use localStorage exclusively

## Database Migration
- Create migration 2025011100 for User, OTPToken tables and Room model updates
- Add indexes for email, display_name, is_private, is_archived, owner_id

## Breaking Changes
- URL parameters now only include username (model/voice moved to localStorage)
- Private rooms require authentication to access
- Room creation can now require authentication (for private rooms)

* Update README with authentication and private room documentation

* Simplify README to be less verbose

* Add missing session import to fix linter errors

* Fix migration dependency to resolve multiple heads conflict

* asdf

* Fix SQLAlchemy auto-correlation error in homepage statistics query

* Change tagline from AI-Powered to Machine Learning Powered

* Add dedicated authentication page instead of modal

- Create new /auth route with full-page authentication flow
- Remove modal code from index.html
- Update Sign in link to point to /auth page
- Auth page has 4-step flow: email, OTP, display name, success
- Better UX with gradient background and cleaner design

* Fix migration: remove batch_alter_table to avoid circular dependency

- Use op.add_column() directly instead of batch_alter_table()
- Remove foreign key constraints (defined in models, not needed in migration)
- User and OTPToken tables created by db.create_all() in make init-db
- Fixes CircularDependencyError during migration

* Fix migration: check if columns exist before adding

- Use inspector to check existing columns and indexes
- Only add columns/indexes if they don't already exist
- Handles case where db.create_all() was run before migration
- Fixes 'duplicate column name' error

* Add profile page, room browsing, and updated_at timestamp

Features:
- Profile page with username change and dark/light mode settings
- Browse page for discovering public and private rooms
- Room updated_at timestamp (integer Unix epoch) that updates on new messages
- Dynamic room tabs based on current room type (public/private)
- Fork and delete room actions moved to right sidebar utility belt
- Remove archive feature and success alerts from room actions

Technical changes:
- Add updated_at column to Room model (integer timestamp)
- Add /profile route with authentication requirement
- Add /browse route for room discovery
- Add API endpoints for username availability check and update
- Update room.updated_at on message creation in app.py:1189
- Wider right sidebar (25% instead of 15%) for better button layout
- Profile link on homepage and browse page for authenticated users

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: russell@unturf. <russell@unturf.com>

static/css/style.css

@@ -179,7 +179,7 @@ p {
 /* Styling for the main container that holds the rooms list and chat */
 .main-container {
     display: grid;
-    grid-template-columns: 15% 70% 15%;
+    grid-template-columns: 15% 60% 25%;
     width: 100%;
     height: 90vh;
 }
@@ -621,3 +621,37 @@ a:hover {
 [data-theme="dark"] * {
     scrollbar-color: #4a4a4a var(--bg-secondary);
 }
+
+/* Room tabs styling */
+#room-tabs {
+    display: grid;
+    grid-template-columns: 1fr 1fr;
+    gap: 0;
+    margin-bottom: 15px;
+    border-bottom: 2px solid var(--border-color);
+}
+
+.room-tab {
+    padding: 10px;
+    text-align: center;
+    cursor: pointer;
+    background-color: var(--bg-tertiary);
+    color: var(--text-secondary);
+    border: none;
+    border-bottom: 3px solid transparent;
+    transition: all 0.3s ease;
+    font-size: 14px;
+    font-weight: 500;
+}
+
+.room-tab:hover {
+    background-color: var(--highlight-bg);
+    color: var(--text-primary);
+}
+
+.room-tab.active {
+    background-color: var(--bg-secondary);
+    color: var(--text-primary);
+    border-bottom-color: var(--button-primary);
+    font-weight: bold;
+}