release: 0.6.6

The live-edge catch-up (8c4f4a0, b4a4c00) landed after the v0.6.5 tag, so
the 0.6.5 artifacts do not contain it — the same gap that left the fix out
of v0.6.4. Cut 0.6.6 so the published build actually carries it.

Local-only changes (no wire change; PROTO planes unchanged), so this is a
PATCH bump per VERSIONING.md.

601 lib tests green, clippy clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "peerspeak"
-version = "0.6.5"
+version = "0.6.6"
 edition = "2024"
 description = "Decentralized peer-to-peer voice chat (Rust/iroh/PipeWire/Opus/iced)"
 license = "MIT"