Add Spotify integration with improved token management and user interface

- Implemented Spotify OAuth handling in spotify_client_manager.py to ensure valid access tokens for users.
- Created helper functions in spotify_helper.py for refreshing tokens and retrieving user information.
- Developed manage_spotify.html template for connecting and managing Spotify accounts, displaying connection status and token information.
- Added logging for token management processes to enhance debugging and monitoring.
- Introduced a debug client for Spotify interactions to facilitate easier testing and development.

TODO.md

@@ -91,7 +91,49 @@
 
 ## 🆕 Upcoming Milestones
 
-### 🎯 Milestone 10: **"Scraper Symphony" Release** – External Music Data
+### 🎯 Milestone 10: **"Import Intelligent" Release** – Enhanced Song Import System
+
+* [ ] Implement parallel playlist import processing
+  * [ ] Design and implement import queue system
+  * [ ] Add background worker system for processing imports
+  * [ ] Enable multiple concurrent import jobs
+  * [ ] Implement priority system for import jobs
+* [ ] Create comprehensive import progress reporting
+  * [ ] Real-time progress indicators for active imports
+  * [ ] Detailed error reporting with recovery options
+  * [ ] Email notifications when imports complete
+* [ ] Redesign Spotify search functionality
+  * [ ] Improve search algorithm and relevance scoring
+  * [ ] Add advanced filtering options (year, genre, etc.)
+  * [ ] Implement caching for frequent searches
+  * [ ] Ensure proper pagination and performance
+* [ ] Add text-based playlist import capability
+  * [ ] Support for pasting plain text playlists
+  * [ ] Line-by-line parsing with artist/song detection
+  * [ ] Confidence scoring for matches
+  * [ ] Manual review interface for low-confidence matches
+  * [ ] Support for various text formats (CSV, plain text, etc.)
+* [ ] Build playlist scraper for "curated" Spotify playlists
+  * [ ] Web scraper for Spotify web interface
+  * [ ] Extract track names and artists from HTML/JSON
+  * [ ] Format compatibility with text-based import
+  * [ ] Handle rate limiting and detection prevention
+* [ ] Implement production-grade web server
+  * [ ] Replace Flask development server with Gunicorn/uWSGI
+  * [ ] Configure proper worker processes and threads
+  * [ ] Implement graceful shutdown and restart capabilities
+  * [ ] Add Nginx as reverse proxy with proper caching
+  * [ ] Set up proper SSL termination and security headers
+  * [ ] Optimize static file serving
+* [ ] Scale database for concurrent operations
+  * [ ] Implement connection pooling
+  * [ ] Add database query optimizations and indexing
+  * [ ] Configure database for concurrent write operations
+  * [ ] Set up monitoring for database performance
+  * [ ] Implement read/write splitting if necessary
+  * [ ] Add database migration safety for zero-downtime upgrades
+
+### 🎯 Milestone 11: **"Scraper Symphony" Release** – External Music Data
 
 * [ ] Identify 2–3 public music chart sources (Billboard, Official Charts, etc.)
 * [ ] Build scraper with user-agent rotation and proxy support
@@ -101,7 +143,7 @@
 * [ ] Store scraper runs and log errors transparently
 * [ ] Add cron-based scheduler for scraper refresh
 
-### 🎯 Milestone 11: **"Alert Amplifier" Release** – Notifications & Emails
+### 🎯 Milestone 12: **"Alert Amplifier" Release** – Notifications & Emails
 
 * [ ] Email verification for new accounts
 * [ ] Notify users when round generation completes
@@ -109,7 +151,7 @@
 * [ ] Optional weekly usage summary for admins
 * [ ] Push notification support via browser or Telegram
 
-### 🎯 Milestone 12: **"Rhythm Roundsmith" Release** – AI-Generated Quiz Rounds
+### 🎯 Milestone 13: **"Rhythm Roundsmith" Release** – AI-Generated Quiz Rounds
 
 * [ ] Develop AI module to generate full quiz rounds
   * [ ] Use existing song metadata (genre, year, tempo, artist)
@@ -122,7 +164,7 @@
 * [ ] Add backend abstraction to swap AI providers (OpenAI, Mistral, etc.)
 * [ ] Build tuning pipeline for prompt quality testing
 
-### 🎯 Milestone 13: **"Storage Sanctuary" Release** – Multi-Provider Storage
+### 🎯 Milestone 14: **"Storage Sanctuary" Release** – Multi-Provider Storage
 
 * [ ] Implement cloud storage backend abstraction
 * [ ] Add support for AWS S3 storage
@@ -131,12 +173,12 @@
 * [ ] Add support for S3-compatible storage (MinIO, Wasabi, etc.)
 * [ ] Integrate Dropbox as a storage backend
 * [ ] Create unified storage management UI
-* [ ] Export backups to cloud storage 
+* [ ] Export backups to cloud storage
 * [ ] Store and retrieve music rounds from cloud storage
 * [ ] Add background synchronization and status tracking
 * [ ] Implement bandwidth-efficient differential uploads
 
-### 🎯 Milestone 14: **"Collaboration Core" Release** – Multi-User Round Sharing
+### 🎯 Milestone 15: **"Collaboration Core" Release** – Multi-User Round Sharing
 
 * [ ] Allow shared editing of rounds
 * [ ] Add collaboration roles (view, comment, edit)
@@ -146,7 +188,7 @@
 * [ ] Allow public view-only sharing links with optional expiration
 * [ ] Display access audit log (who opened/edited and when)
 
-### 🎯 Milestone 15: **"Profile Personalizer" Release** – User Preferences & Tagging
+### 🎯 Milestone 16: **"Profile Personalizer" Release** – User Preferences & Tagging
 
 * [x] User-specific intro/outro/replay MP3 fallback system
 * [x] Persistent custom user settings
@@ -155,7 +197,7 @@
 * [ ] Add filtering and sorting by tag
 * [ ] Dark mode toggle
 
-### 🎯 Milestone 16: **"Performance Pulse" Release** – Scaling & Speed
+### 🎯 Milestone 17: **"Performance Pulse" Release** – Scaling & Speed
 
 * [ ] Index high-traffic database fields (tags, dates, users)
 * [ ] Paginate round/song lists
@@ -163,7 +205,7 @@
 * [ ] Add Redis/memory cache layer for read-heavy endpoints
 * [ ] Load test with simulated users and large playlists
 
-### 🎯 Milestone 17: **"Deployment Dynamo" Release** – CI/CD and Maintenance
+### 🎯 Milestone 18: **"Deployment Dynamo" Release** – CI/CD and Maintenance
 
 * [ ] GitHub Actions or GitLab CI/CD pipeline for builds and tests
 * [ ] Nightly backup job with status alert
@@ -186,5 +228,5 @@
   * [ ] Implement keyboard shortcuts in the application
   * [ ] Document keyboard shortcuts for power users when implemented
 
-*Last updated: May 12, 2025*
+*Last updated: May 14, 2025*