chore: rename project quicnprotochat -> quicproquo (binaries: qpq)

Rename the entire workspace:
- Crate packages: quicnprotochat-{core,proto,server,client,gui,p2p,mobile} -> quicproquo-*
- Binary names: quicnprotochat -> qpq, quicnprotochat-server -> qpq-server,
  quicnprotochat-gui -> qpq-gui
- Default files: *-state.bin -> qpq-state.bin, *-server.toml -> qpq-server.toml,
  *.db -> qpq.db
- Environment variable prefix: QUICNPROTOCHAT_* -> QPQ_*
- App identifier: chat.quicnproto.gui -> chat.quicproquo.gui
- Proto package: quicnprotochat.bench -> quicproquo.bench
- All documentation, Docker, CI, and script references updated

HKDF domain-separation strings and P2P ALPN remain unchanged for
backward compatibility with existing encrypted state and wire protocol.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/src/protocol-layers/overview.md

@@ -1,6 +1,6 @@
 # Protocol Layers Overview
 
-quicnprotochat composes four distinct protocol layers into a single security stack. Each layer addresses a specific class of threat and delegates everything else to the layers above or below it. No single layer is sufficient on its own; the composition is what delivers end-to-end confidentiality, server authentication, forward secrecy, post-compromise security, and post-quantum resistance.
+quicproquo composes four distinct protocol layers into a single security stack. Each layer addresses a specific class of threat and delegates everything else to the layers above or below it. No single layer is sufficient on its own; the composition is what delivers end-to-end confidentiality, server authentication, forward secrecy, post-compromise security, and post-quantum resistance.
 
 This page provides a high-level comparison and a suggested reading order. The deep-dive pages that follow contain implementation details drawn directly from the source code.
 
@@ -47,7 +47,7 @@ The pages in this section are ordered to build understanding incrementally:
 
 1. **[QUIC + TLS 1.3](quic-tls.md)** -- Start here. This is the transport layer that every client-server connection uses. Understanding QUIC stream multiplexing and the TLS 1.3 handshake is prerequisite to understanding how Cap'n Proto RPC rides on top.
 
-2. **[MLS (RFC 9420)](mls.md)** -- The core cryptographic innovation. MLS provides the group key agreement that makes quicnprotochat an E2E encrypted group messenger rather than just a transport-encrypted relay. This is the longest and most detailed page.
+2. **[MLS (RFC 9420)](mls.md)** -- The core cryptographic innovation. MLS provides the group key agreement that makes quicproquo an E2E encrypted group messenger rather than just a transport-encrypted relay. This is the longest and most detailed page.
 
 3. **[Cap'n Proto Serialisation and RPC](capn-proto.md)** -- The serialisation and RPC layer that bridges MLS application data with the transport. Understanding the Envelope schema, the ParsedEnvelope owned type, and the NodeService RPC interface is essential for reading the server and client source code.
 
@@ -70,9 +70,9 @@ Each protocol layer maps to one or more workspace crates:
 
 | Layer | Primary Crate | Source File(s) |
 |---|---|---|
-| QUIC + TLS 1.3 | `quicnprotochat-server`, `quicnprotochat-client` | `main.rs` (server and client entry points) |
-| Cap'n Proto | `quicnprotochat-proto` | `src/lib.rs`, `build.rs`, `schemas/*.capnp` |
-| MLS | `quicnprotochat-core` | `src/group.rs`, `src/keystore.rs` |
-| Hybrid KEM | `quicnprotochat-core` | `src/hybrid_kem.rs` |
+| QUIC + TLS 1.3 | `quicproquo-server`, `quicproquo-client` | `main.rs` (server and client entry points) |
+| Cap'n Proto | `quicproquo-proto` | `src/lib.rs`, `build.rs`, `schemas/*.capnp` |
+| MLS | `quicproquo-core` | `src/group.rs`, `src/keystore.rs` |
+| Hybrid KEM | `quicproquo-core` | `src/hybrid_kem.rs` |
 
 For a full crate responsibility breakdown, see [Crate Responsibilities](../architecture/crate-responsibilities.md).