Rebuild frontend with Tailwind CSS + fix Python 3.14 compatibility

- Upgrade SQLAlchemy 2.0.27→2.0.45, google-genai SDK for Python 3.14
- Replace google-generativeai with google-genai in narrative_service.py
- Fix HTTPException handling in main.py (was wrapping as 500)
- Rebuild all frontend components with Tailwind CSS v3:
  - Dashboard, NarrativeSection, StatsGrid, VibeRadar, HeatMap, TopRotation
  - Custom color palette (background-dark, card-dark, accent-neon, etc.)
  - Add glass-panel, holographic-badge CSS effects
- Docker improvements:
  - Combined backend container (API + worker in entrypoint.sh)
  - DATABASE_URL configurable via env var
  - CI workflow builds both backend and frontend images
- Update README with clearer docker-compose instructions

backend/alembic/env.py

@@ -10,29 +10,17 @@ from alembic import context
 # Add app to path to import models
 sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
-from app.database import Base
-from app.models import * # Import models to register them
+from app.database import Base, SQLALCHEMY_DATABASE_URL
+from app.models import *
 
-# this is the Alembic Config object, which provides
-# access to the values within the .ini file in use.
 config = context.config
 
-# Interpret the config file for Python logging.
-# This line sets up loggers basically.
 if config.config_file_name is not None:
     fileConfig(config.config_file_name)
 
-# add your model's MetaData object here
-# for 'autogenerate' support
 target_metadata = Base.metadata
 
-# other values from the config, defined by the needs of env.py,
-# can be acquired:
-# my_important_option = config.get_main_option("my_important_option")
-# ... etc.
-
-# Override sqlalchemy.url with our app's URL
-config.set_main_option("sqlalchemy.url", "sqlite:///./music.db")
+config.set_main_option("sqlalchemy.url", SQLALCHEMY_DATABASE_URL)
 
 
 def run_migrations_offline() -> None: