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

docs/src/design-rationale/adr-006-rest-gateway.md

@@ -6,7 +6,7 @@ Accepted (supersedes earlier REST gateway proposal)
 
 ## Context
 
-quicproquo uses QUIC + Cap'n Proto RPC as its native protocol. This
+quicprochat uses QUIC + Cap'n Proto RPC as its native protocol. This
 combination delivers zero-copy serialization, multiplexed streams, and
 sub-RTT connection establishment — ideal for high-performance clients.
 
@@ -58,11 +58,11 @@ Both paths use QUIC transport. The project name stays honest.
 
 ### Crypto layer distribution
 
-MLS encryption/decryption must happen client-side. The `quicproquo-core`
+MLS encryption/decryption must happen client-side. The `quicprochat-core`
 crate is compiled to:
 
 - **WASM** — for browsers, Node.js, Deno
-- **C FFI** (`libquicproquo`) — for Swift, Kotlin, Python, Go (via cgo)
+- **C FFI** (`libquicprochat`) — for Swift, Kotlin, Python, Go (via cgo)
 - **Native Rust** — for Rust clients (existing)
 
 ### Why not REST?
@@ -104,9 +104,9 @@ gRPC may be reconsidered for server-to-server federation (Phase 7.3).
 
 ### Neutral
 
-- SDKs live in separate repositories (e.g., `quicproquo-go`,
-  `quicproquo-py`) to avoid bloating the core workspace.
-- The C FFI crate (`quicproquo-ffi`) bundles both crypto and transport,
+- SDKs live in separate repositories (e.g., `quicprochat-go`,
+  `quicprochat-py`) to avoid bloating the core workspace.
+- The C FFI crate (`quicprochat-ffi`) bundles both crypto and transport,
   so language bindings only need to call C functions.
 
 ## Related