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-rpc/src/lib.rs

@@ -0,0 +1,15 @@
+//! QUIC RPC framework for quicprochat v2.
+//!
+//! Wire format per QUIC stream:
+//! - Request:  `[method_id: u16][request_id: u32][payload_len: u32][protobuf bytes]`
+//! - Response: `[status: u8][request_id: u32][payload_len: u32][protobuf bytes]`
+//! - Push:     `[event_type: u16][payload_len: u32][protobuf bytes]` (uni-stream)
+
+pub mod auth_handshake;
+pub mod framing;
+pub mod method;
+pub mod server;
+pub mod client;
+pub mod middleware;
+pub mod push;
+pub mod error;