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/check.hpp

@@ -0,0 +1,53 @@
+#pragma once
+
+// Minimal test harness: CHECK accumulates failures, TEST_MAIN reports and sets the exit
+// code. Deliberately tiny — the daemon does not pull in a test framework for this.
+
+#include <cstdio>
+#include <string>
+#include <vector>
+
+namespace veloxd_test {
+
+inline std::vector<std::string>& failures() {
+    static std::vector<std::string> f;
+    return f;
+}
+inline int& checks() {
+    static int n = 0;
+    return n;
+}
+
+}  // namespace veloxd_test
+
+#define CHECK(cond)                                                                     \
+    do {                                                                               \
+        ++::veloxd_test::checks();                                                     \
+        if (!(cond)) {                                                                 \
+            ::veloxd_test::failures().push_back(std::string(__FILE__) + ":" +          \
+                                               std::to_string(__LINE__) + ": " + #cond); \
+        }                                                                              \
+    } while (0)
+
+#define CHECK_EQ(a, b)                                                                  \
+    do {                                                                               \
+        ++::veloxd_test::checks();                                                     \
+        auto _va = (a);                                                                \
+        auto _vb = (b);                                                                \
+        if (!(_va == _vb)) {                                                           \
+            ::veloxd_test::failures().push_back(std::string(__FILE__) + ":" +          \
+                                               std::to_string(__LINE__) + ": " + #a +  \
+                                               " == " + #b);                           \
+        }                                                                              \
+    } while (0)
+
+#define TEST_MAIN()                                                                     \
+    int main() {                                                                        \
+        run();                                                                          \
+        for (const auto& f : ::veloxd_test::failures()) std::printf("FAIL %s\n", f.c_str()); \
+        std::printf("%d/%d checks passed\n",                                            \
+                    ::veloxd_test::checks() -                                           \
+                        static_cast<int>(::veloxd_test::failures().size()),             \
+                    ::veloxd_test::checks());                                           \
+        return ::veloxd_test::failures().empty() ? 0 : 1;                               \
+    }