chore: rename quicproquo → quicprochat in Rust workspace

Rename all crate directories, package names, binary names, proto
package/module paths, ALPN strings, env var prefixes, config filenames,
mDNS service names, and plugin ABI symbols from quicproquo/qpq to
quicprochat/qpc.

crates/quicprochat-client/src/client/mod.rs

@@ -0,0 +1,24 @@
+pub mod command_engine;
+pub mod commands;
+pub mod conversation;
+pub mod display;
+pub mod hex;
+pub mod mesh_discovery;
+#[cfg(feature = "playbook")]
+pub mod playbook;
+pub mod repl;
+pub mod retry;
+pub mod rpc;
+pub mod session;
+pub mod state;
+pub mod token_cache;
+#[cfg(feature = "tui")]
+pub mod tui;
+#[cfg(feature = "v2")]
+pub mod v2_repl;
+#[cfg(all(feature = "v2", feature = "tui"))]
+pub mod v2_tui;
+
+pub use commands::*;
+pub use rpc::{connect_node, enqueue, fetch_all, fetch_hybrid_key, fetch_key_package, fetch_wait, upload_hybrid_key, upload_key_package};
+pub use state::{decode_identity_key, load_existing_state, load_or_init_state, save_state};