feat(proxy-engine): integrate Kokoro TTS generation into proxy-engine and simplify TypeScript prompt handling to use cached WAV files

rust/crates/codec-lib/src/lib.rs

@@ -1,7 +1,7 @@
 //! Audio codec library for the SIP router.
 //!
 //! Handles Opus ↔ G.722 ↔ PCMU/PCMA transcoding with ML noise suppression.
-//! Used by both the standalone `opus-codec` CLI and the `proxy-engine` binary.
+//! Used by the `proxy-engine` binary for all audio transcoding.
 
 use audiopus::coder::{Decoder as OpusDecoder, Encoder as OpusEncoder};
 use audiopus::packet::Packet as OpusPacket;