Fixes volume issues on YouTube and other sites that run their own audio pipeline:

• At default settings (100%, no effects) VolMax now stays out of the way, so the site's own volume slider continues to work normally.
• When you open the popup, the slider syncs to the page's current volume, so any drag is relative to the real audio level instead of a stale 100% default.
• Volume and mute changes ramp smoothly over 50ms, removing clicks and the loud jump that could happen when the extension first engaged.
• Fixed a long-standing bug where captured audio played quieter than the page had set (the extension's gain and the native volume were both scaling the signal).