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/Dockerfile.chat-test

@@ -12,45 +12,45 @@ WORKDIR /build
 
 # Copy manifests first so dependency layers are cached independently of source.
 COPY Cargo.toml Cargo.lock ./
-COPY crates/quicnprotochat-core/Cargo.toml   crates/quicnprotochat-core/Cargo.toml
-COPY crates/quicnprotochat-proto/Cargo.toml  crates/quicnprotochat-proto/Cargo.toml
-COPY crates/quicnprotochat-server/Cargo.toml crates/quicnprotochat-server/Cargo.toml
-COPY crates/quicnprotochat-client/Cargo.toml crates/quicnprotochat-client/Cargo.toml
-COPY crates/quicnprotochat-p2p/Cargo.toml    crates/quicnprotochat-p2p/Cargo.toml
+COPY crates/quicproquo-core/Cargo.toml   crates/quicproquo-core/Cargo.toml
+COPY crates/quicproquo-proto/Cargo.toml  crates/quicproquo-proto/Cargo.toml
+COPY crates/qpq-server/Cargo.toml crates/qpq-server/Cargo.toml
+COPY crates/quicproquo-client/Cargo.toml crates/quicproquo-client/Cargo.toml
+COPY crates/quicproquo-p2p/Cargo.toml    crates/quicproquo-p2p/Cargo.toml
 
 # Create dummy source files so `cargo build` can resolve the dependency graph
 # and cache the compiled dependencies before copying real source.
 RUN mkdir -p \
-        crates/quicnprotochat-core/src \
-        crates/quicnprotochat-proto/src \
-        crates/quicnprotochat-server/src \
-        crates/quicnprotochat-client/src \
-        crates/quicnprotochat-p2p/src \
-    && echo 'fn main() {}' > crates/quicnprotochat-server/src/main.rs \
-    && echo 'fn main() {}' > crates/quicnprotochat-client/src/main.rs \
-    && touch crates/quicnprotochat-core/src/lib.rs \
-    && touch crates/quicnprotochat-proto/src/lib.rs \
-    && touch crates/quicnprotochat-p2p/src/lib.rs
+        crates/quicproquo-core/src \
+        crates/quicproquo-proto/src \
+        crates/qpq-server/src \
+        crates/quicproquo-client/src \
+        crates/quicproquo-p2p/src \
+    && echo 'fn main() {}' > crates/qpq-server/src/main.rs \
+    && echo 'fn main() {}' > crates/quicproquo-client/src/main.rs \
+    && touch crates/quicproquo-core/src/lib.rs \
+    && touch crates/quicproquo-proto/src/lib.rs \
+    && touch crates/quicproquo-p2p/src/lib.rs
 
 # Schemas must exist before the proto crate's build.rs runs.
 COPY schemas/ schemas/
 
 # Build dependencies only (source stubs mean this layer is cache-friendly).
 # The GUI crate is not included, so workspace resolution may fail — || true handles it.
-RUN cargo build --release --bin quicnprotochat-server --bin quicnprotochat 2>/dev/null || true
+RUN cargo build --release --bin qpq-server --bin qpq 2>/dev/null || true
 
 # Copy real source and build for real.
 COPY crates/ crates/
 
 # Touch source to force re-compilation after copying real crates.
 RUN touch \
-        crates/quicnprotochat-core/src/lib.rs \
-        crates/quicnprotochat-proto/src/lib.rs \
-        crates/quicnprotochat-p2p/src/lib.rs \
-        crates/quicnprotochat-server/src/main.rs \
-        crates/quicnprotochat-client/src/main.rs
+        crates/quicproquo-core/src/lib.rs \
+        crates/quicproquo-proto/src/lib.rs \
+        crates/quicproquo-p2p/src/lib.rs \
+        crates/qpq-server/src/main.rs \
+        crates/quicproquo-client/src/main.rs
 
-RUN cargo build --release --bin quicnprotochat-server --bin quicnprotochat
+RUN cargo build --release --bin qpq-server --bin qpq
 
 # ── Stage 2: Runtime ──────────────────────────────────────────────────────────
 #
@@ -61,8 +61,8 @@ RUN apt-get update \
     && apt-get install -y --no-install-recommends ca-certificates \
     && rm -rf /var/lib/apt/lists/*
 
-COPY --from=builder /build/target/release/quicnprotochat-server /usr/local/bin/quicnprotochat-server
-COPY --from=builder /build/target/release/quicnprotochat        /usr/local/bin/quicnprotochat
+COPY --from=builder /build/target/release/qpq-server /usr/local/bin/qpq-server
+COPY --from=builder /build/target/release/qpq        /usr/local/bin/qpq
 
 RUN mkdir -p /chat