chore: rename quicproquo → quicprochat in docs, Docker, CI, and packaging

Rename all project references from quicproquo/qpq to quicprochat/qpc
across documentation, Docker configuration, CI workflows, packaging
scripts, operational configs, and build tooling.

- Docker: crate paths, binary names, user/group, data dirs, env vars
- CI: workflow crate references, binary names, artifact names
- Docs: all markdown files under docs/, SDK READMEs, book.toml
- Packaging: OpenWrt Makefile, init script, UCI config (file renames)
- Scripts: justfile, dev-shell, screenshot, cross-compile, ai_team
- Operations: Prometheus config, alert rules, Grafana dashboard
- Config: .env.example (QPQ_* → QPC_*), CODEOWNERS paths
- Top-level: README, CONTRIBUTING, ROADMAP, CLAUDE.md

scripts/cross-compile.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Cross-compile quicproquo for musl targets (OpenWrt / embedded Linux).
+# Cross-compile quicprochat for musl targets (OpenWrt / embedded Linux).
 #
 # Produces statically linked, stripped binaries optimised for size.
 # Requires: cargo-zigbuild (preferred) or cross.
@@ -8,7 +8,7 @@
 #   ./scripts/cross-compile.sh                    # all targets
 #   ./scripts/cross-compile.sh x86_64-unknown-linux-musl  # single target
 #
-# Output: target/<triple>/release/qpq-server (stripped)
+# Output: target/<triple>/release/qpc-server (stripped)
 
 set -euo pipefail
 
@@ -47,7 +47,7 @@ SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
 cd "$PROJECT_ROOT"
 
-echo "=== quicproquo cross-compilation ==="
+echo "=== quicprochat cross-compilation ==="
 echo "Build tool: $BUILD_CMD"
 echo "Targets: ${TARGETS[*]}"
 echo ""
@@ -55,8 +55,8 @@ echo ""
 FAILED=()
 for target in "${TARGETS[@]}"; do
     echo "--- Building for $target ---"
-    if $BUILD_CMD --release --target "$target" --bin qpq-server; then
-        BINARY="target/$target/release/qpq-server"
+    if $BUILD_CMD --release --target "$target" --bin qpc-server; then
+        BINARY="target/$target/release/qpc-server"
         if [ -f "$BINARY" ]; then
             SIZE=$(stat -c%s "$BINARY" 2>/dev/null || stat -f%z "$BINARY")
             SIZE_MB=$(echo "scale=2; $SIZE / 1048576" | bc)