refactor: use LazyLock instead of OnceLock

[justmangoou]

• chore(optimization): add strip and lto, remove unnecessary features #20
• feat: implement Soundboard action #16
• feat: implement Notification action #18

Summarize

• Replaced OnceLock with LazyLock.
• Remove RwLock for RECONNECTING_FLAG.
• Centralized all states (VoiceSettings, VoiceMode, etc...) to client.rs.
• Move audio_device_utils.rs to src/, actions package should not contain utilities.
• Use Mutex instead of RwLock for DISCORD_CLIENT because it only writes.

[nekename]

👍

this codebase is the work of Claude Opus 4.6 with extensive manual review, but no manual refactoring - if it worked it worked