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/SUMMARY.md

@@ -4,7 +4,7 @@
 
 ---
 
-# Why quicnprotochat?
+# Why quicproquo?
 
 - [Comparison with Classical Chat Protocols](design-rationale/protocol-comparison.md)
 - [Why This Design, Not Signal/Matrix/...](design-rationale/why-not-signal.md)
@@ -71,6 +71,7 @@
 - [ADR-002: Cap'n Proto over MessagePack](design-rationale/adr-002-capnproto.md)
 - [ADR-004: MLS-Unaware Delivery Service](design-rationale/adr-004-mls-unaware-ds.md)
 - [ADR-005: Single-Use KeyPackages](design-rationale/adr-005-single-use-keypackages.md)
+- [ADR-006: SDK-First Adoption (No REST Gateway)](design-rationale/adr-006-rest-gateway.md)
 
 ---
 
@@ -92,6 +93,7 @@
 - [Auth, Devices, and Tokens](roadmap/authz-plan.md)
 - [1:1 Channel Design](roadmap/dm-channels.md)
 - [Future Research Directions](roadmap/future-research.md)
+- [Full Roadmap (Phases 1–8)](../../ROADMAP.md)
 
 ---