Fix audio timestamp continuity issue with Type 3 RTMP headers

Restores missing timeDelta inheritance for Type 3 (HEADER_CONTINUE) headers
that was inadvertently removed in recent extended timestamp handling updates.

Issue: Audio timestamps were staying at zero when listeners were added to
ClientBroadcastStream, while video timestamps continued to increment properly.

Root cause: Recent commits ee0f546 and 0a89fdc fixed extended timestamp
handling but accidentally broke Type 3 header processing by failing to
inherit timeDelta from the previous header. Type 3 headers must inherit
both timeBase and timeDelta to maintain proper RTMP timestamp continuity.

Impact: Audio packets frequently use Type 3 headers for efficiency, so
this affected audio synchronization more than video (which typically
uses Type 0/1 headers with absolute timestamps).

Fix: Added timeDelta = lastHeader.getTimerDelta() to restore proper
inheritance as required by RTMP specification and librtmp compatibility.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: mondain

common/src/main/java/org/red5/server/net/rtmp/codec/RTMPProtocolDecoder.java

@@ -401,6 +401,8 @@ public Header decodeHeader(ChunkHeader chh, RTMPDecodeState state, IoBuffer in,
         if (lastHeader != null) {
             // time base from last header
             timeBase = lastHeader.getTimerBase();
+            // inherit the time delta from last header (critical for Type 3 headers)
+            timeDelta = lastHeader.getTimerDelta();
             // inherit the stream id from the last header
             header.setStreamId(lastHeader.getStreamId());
             // inherit the data type from the last header