fix: extract snapshot data from chunks, reduce ClickHouse log noise

- ChunkAccumulator now extracts inputBody/outputBody/inputHeaders/outputHeaders
  from ExecutionChunk.inputSnapshot/outputSnapshot instead of storing empty strings
- Set ClickHouse server log level to warning (was trace by default)
- Update CLAUDE.md to document Ed25519 key derivation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer3-server-core/src/main/java/com/cameleer3/server/core/ingestion/ChunkAccumulator.java

@@ -1,5 +1,6 @@
 package com.cameleer3.server.core.ingestion;
 
+import com.cameleer3.common.model.ExchangeSnapshot;
 import com.cameleer3.common.model.ExecutionChunk;
 import com.cameleer3.common.model.FlatProcessorRecord;
 import com.cameleer3.server.core.storage.DiagramStore;
@@ -140,6 +141,8 @@ public class ChunkAccumulator {
         merged.setSpanId(coalesce(newer.getSpanId(), older.getSpanId()));
         merged.setOriginalExchangeId(coalesce(newer.getOriginalExchangeId(), older.getOriginalExchangeId()));
         merged.setReplayExchangeId(coalesce(newer.getReplayExchangeId(), older.getReplayExchangeId()));
+        merged.setInputSnapshot(coalesce(newer.getInputSnapshot(), older.getInputSnapshot()));
+        merged.setOutputSnapshot(coalesce(newer.getOutputSnapshot(), older.getOutputSnapshot()));
         merged.setChunkSeq(Math.max(newer.getChunkSeq(), older.getChunkSeq()));
         merged.setFinal(newer.isFinal() || older.isFinal());
         merged.setProcessors(List.of());  // processors are handled separately
@@ -182,10 +185,10 @@ public class ChunkAccumulator {
                 envelope.getRootCauseMessage(),
                 diagramHash,
                 envelope.getEngineLevel(),
-                "",  // inputBody — on processor records now
-                "",  // outputBody
-                "",  // inputHeaders
-                "",  // outputHeaders
+                extractBody(envelope.getInputSnapshot()),
+                extractBody(envelope.getOutputSnapshot()),
+                extractHeaders(envelope.getInputSnapshot()),
+                extractHeaders(envelope.getOutputSnapshot()),
                 serializeAttributes(envelope.getAttributes()),
                 envelope.getTraceId(),
                 envelope.getSpanId(),
@@ -196,6 +199,21 @@ public class ChunkAccumulator {
         );
     }
 
+    private static String extractBody(ExchangeSnapshot snapshot) {
+        if (snapshot == null || snapshot.getBody() == null) return "";
+        return snapshot.getBody();
+    }
+
+    private static String extractHeaders(ExchangeSnapshot snapshot) {
+        if (snapshot == null || snapshot.getHeaders() == null) return "";
+        try {
+            return MAPPER.writeValueAsString(snapshot.getHeaders());
+        } catch (JsonProcessingException e) {
+            log.warn("Failed to serialize snapshot headers", e);
+            return "";
+        }
+    }
+
     private static String serializeAttributes(Map<String, String> attributes) {
         if (attributes == null || attributes.isEmpty()) {
             return "{}";