完善客户端功能并同步差距文档

extension/tests/net_classic_stream_test.cpp

@@ -78,6 +78,30 @@ int main() {
 		CHECK(out[sizeof(Handshake)] == SEQUENCE_TABLE[0], "time-sync uses next sequence byte");
 	}
 
+	// -------------------------------------------- server frame clock (§3.2)
+	{
+		ClassicStream s;
+		CHECK(s.server_frame_ms() == 0, "server_frame_ms is 0 before any handshake");
+		CHECK(!s.has_server_clock(), "has_server_clock false before handshake");
+
+		Handshake hs{};
+		hs.header = HDR_HANDSHAKE;
+		hs.handshake = 0x1234;
+		hs.time = 500000;
+		hs.delta = 20;
+		auto b = raw(hs);
+		s.feed(b.data(), b.size());
+		(void)drain(s);
+
+		CHECK(s.has_server_clock(), "has_server_clock true after handshake");
+		uint32_t base = 500000u + 20u; // hs.time + lDelta
+		uint32_t f1 = s.server_frame_ms();
+		CHECK(f1 >= base && f1 < base + 5000u,
+				"server_frame_ms ~ hs.time + lDelta right after handshake");
+		uint32_t f2 = s.server_frame_ms();
+		CHECK(f2 >= f1, "server frame clock is monotonic non-decreasing");
+	}
+
 	// ---------------------------------------------------------- GC_PHASE
 	{
 		ClassicStream s;