chore(config): update speaches config and ignore sveltekit dashboard

- Simplified .env.example to use localhost SPEACHES_URL
- Removed unused prod_url from SpeachesSettings config
- Added dashboard node_modules and build dirs to .gitignore
- Streamlines local development setup

config.py

@@ -37,7 +37,6 @@ class SpeachesSettings(BaseSettings):
     model_config = SettingsConfigDict(env_prefix="SPEACHES_")
 
     url: str = "http://localhost:22070"
-    prod_url: str = "http://localhost:22070"
     model: str = "whisper-large-v3"