daemon: rpc/ — Unix-socket transport + generated dispatch wiring (build step 1)

First real code in daemon/. veloxd now listens on
$XDG_RUNTIME_DIR/velox/velox.sock (0600, SO_PEERCRED same-UID check),
frames NDJSON, and routes every method through the generated
velox::proto::dispatch(). The CLI and GUI have a server to talk to.

Modules:
- rpc/ndjson.hpp    — newline-delimited framing, 8 MiB frame cap, CRLF-
                       tolerant, partial-tail buffering. Header-only, tested.
- rpc/event_loop    — single-threaded poll(2) reactor; never blocks the
                       loop. stop()/wake() are async-signal-safe (eventfd).
- rpc/runtime_dir   — $XDG_RUNTIME_DIR/velox resolution, 0700, owner-checked;
                       refuses an insecure fallback rather than using /tmp.
- rpc/uds_server    — listener + non-blocking per-conn read/write with
                       backpressure; handles session.hello (protocol-major
                       check -> -32001, sessionId, transport=uds) and
                       session.subscribe in the server layer; routes the
                       rest through dispatch().
- rpc/dispatcher    — VeloxDispatcher : proto::Dispatcher, all 39 methods.
                       download.list answers an empty table; the rest return
                       "not implemented" (-> -32603) until the store lands.
- main.cpp          — abstract-namespace single-instance lock, signal ->
                       clean shutdown, socket unlinked on exit.

Tests (ASan+UBSan and TSan clean):
- veloxd.ndjson         — framing edge cases
- veloxd.uds_roundtrip  — real socket: hello ok / version mismatch / empty
                          list / -32601 / -32700 / pipelined requests, and a
                          guard on the -32603 collapse documented in P1.

Known gap, filed not worked around: daemon/docs/proto-requests-m1.md P1 —
the generated Dispatcher has no error channel below -32603, so handlers
cannot yet return -32010/-32011/-32013 with their data payloads. The
server layer handles -32001/-32002/-32003 around dispatch(); genuine
in-handler errors collapse to -32603 until PROTO gives handlers a real
error return. Three error fixtures are non-conformant until then.

Not in this drop: rpc/ws_server (next; needs the store for hashed pairing
tokens), store/, sched/, cli/. WS reuses this event loop.

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Upd9WhG9oppieig5nRDLig

daemon/tests/CMakeLists.txt

@@ -0,0 +1,14 @@
+# daemon unit + integration tests. Registered with ctest; run via `ctest --preset dev`.
+# No external test framework — each file is a small self-checking binary (matches the
+# lightweight style core/ uses, without depending on core's private test support).
+
+add_executable(veloxd_ndjson_test ndjson_test.cpp)
+target_link_libraries(veloxd_ndjson_test PRIVATE veloxd_rpc)
+target_compile_options(veloxd_ndjson_test PRIVATE -Wall -Wextra -Wpedantic -Werror)
+add_test(NAME veloxd.ndjson COMMAND veloxd_ndjson_test)
+
+add_executable(veloxd_uds_roundtrip_test uds_roundtrip_test.cpp)
+target_link_libraries(veloxd_uds_roundtrip_test PRIVATE veloxd_rpc)
+target_compile_options(veloxd_uds_roundtrip_test PRIVATE -Wall -Wextra -Wpedantic -Werror)
+add_test(NAME veloxd.uds_roundtrip COMMAND veloxd_uds_roundtrip_test)
+set_tests_properties(veloxd.uds_roundtrip PROPERTIES TIMEOUT 30)