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>

docker/docker-compose.chat-test.yml

@@ -14,7 +14,7 @@ services:
       context: ..
       dockerfile: docker/Dockerfile.chat-test
     command: >-
-      quicnprotochat-server
+      qpq-server
         --listen 0.0.0.0:7000
         --data-dir /data
         --tls-cert /data/server-cert.der
@@ -43,10 +43,10 @@ services:
     entrypoint: ["sleep", "infinity"]
     environment:
       RUST_LOG: warn
-      QUICNPROTOCHAT_ACCESS_TOKEN: devtoken
-      QUICNPROTOCHAT_CA_CERT: /data/server-cert.der
-      QUICNPROTOCHAT_SERVER_NAME: localhost
-      QUICNPROTOCHAT_SERVER: "server:7000"
+      QPQ_ACCESS_TOKEN: devtoken
+      QPQ_CA_CERT: /data/server-cert.der
+      QPQ_SERVER_NAME: localhost
+      QPQ_SERVER: "server:7000"
     volumes:
       - server-data:/data:ro
     working_dir: /chat
@@ -65,10 +65,10 @@ services:
     entrypoint: ["sleep", "infinity"]
     environment:
       RUST_LOG: warn
-      QUICNPROTOCHAT_ACCESS_TOKEN: devtoken
-      QUICNPROTOCHAT_CA_CERT: /data/server-cert.der
-      QUICNPROTOCHAT_SERVER_NAME: localhost
-      QUICNPROTOCHAT_SERVER: "server:7000"
+      QPQ_ACCESS_TOKEN: devtoken
+      QPQ_CA_CERT: /data/server-cert.der
+      QPQ_SERVER_NAME: localhost
+      QPQ_SERVER: "server:7000"
     volumes:
       - server-data:/data:ro
     working_dir: /chat