feat: persist and display exchange properties from agent

Add support for exchange properties sent by the agent alongside headers.
Properties flow through the same pipeline as headers: ClickHouse columns
(input_properties, output_properties) on both executions and
processor_executions tables, MergedExecution record, ChunkAccumulator
extraction, DetailService snapshot, and REST API response.

UI adds a Properties tab next to Headers in the process diagram detail
panel, with the same input/output split table layout.

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

cameleer3-server-core/src/main/java/com/cameleer3/server/core/detail/DetailService.java

@@ -44,6 +44,7 @@ public class DetailService {
                             exec.diagramContentHash(), processors,
                             exec.inputBody(), exec.outputBody(),
                             exec.inputHeaders(), exec.outputHeaders(),
+                            exec.inputProperties(), exec.outputProperties(),
                             parseAttributes(exec.attributes()),
                             exec.errorType(), exec.errorCategory(),
                             exec.rootCauseType(), exec.rootCauseMessage(),
@@ -54,26 +55,23 @@ public class DetailService {
 
     public Optional<Map<String, String>> getProcessorSnapshot(String executionId, String processorId) {
         return executionStore.findProcessorById(executionId, processorId)
-            .map(p -> {
-                Map<String, String> snapshot = new LinkedHashMap<>();
-                if (p.inputBody() != null) snapshot.put("inputBody", p.inputBody());
-                if (p.outputBody() != null) snapshot.put("outputBody", p.outputBody());
-                if (p.inputHeaders() != null) snapshot.put("inputHeaders", p.inputHeaders());
-                if (p.outputHeaders() != null) snapshot.put("outputHeaders", p.outputHeaders());
-                return snapshot;
-            });
+            .map(DetailService::snapshotFromRecord);
     }
 
     public Optional<Map<String, String>> getProcessorSnapshotBySeq(String executionId, int seq) {
         return executionStore.findProcessorBySeq(executionId, seq)
-            .map(p -> {
-                Map<String, String> snapshot = new LinkedHashMap<>();
-                if (p.inputBody() != null) snapshot.put("inputBody", p.inputBody());
-                if (p.outputBody() != null) snapshot.put("outputBody", p.outputBody());
-                if (p.inputHeaders() != null) snapshot.put("inputHeaders", p.inputHeaders());
-                if (p.outputHeaders() != null) snapshot.put("outputHeaders", p.outputHeaders());
-                return snapshot;
-            });
+            .map(DetailService::snapshotFromRecord);
+    }
+
+    private static Map<String, String> snapshotFromRecord(ProcessorRecord p) {
+        Map<String, String> snapshot = new LinkedHashMap<>();
+        if (p.inputBody() != null) snapshot.put("inputBody", p.inputBody());
+        if (p.outputBody() != null) snapshot.put("outputBody", p.outputBody());
+        if (p.inputHeaders() != null) snapshot.put("inputHeaders", p.inputHeaders());
+        if (p.outputHeaders() != null) snapshot.put("outputHeaders", p.outputHeaders());
+        if (p.inputProperties() != null) snapshot.put("inputProperties", p.inputProperties());
+        if (p.outputProperties() != null) snapshot.put("outputProperties", p.outputProperties());
+        return snapshot;
     }
 
     /** Parse the raw processor tree JSON stored alongside the execution. */

cameleer3-server-core/src/main/java/com/cameleer3/server/core/detail/ExecutionDetail.java

@@ -47,6 +47,8 @@ public record ExecutionDetail(
         String outputBody,
         String inputHeaders,
         String outputHeaders,
+        String inputProperties,
+        String outputProperties,
         Map<String, String> attributes,
         String errorType,
         String errorCategory,

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

@@ -201,6 +201,8 @@ public class ChunkAccumulator {
                 extractBody(envelope.getOutputSnapshot()),
                 extractHeaders(envelope.getInputSnapshot()),
                 extractHeaders(envelope.getOutputSnapshot()),
+                extractProperties(envelope.getInputSnapshot()),
+                extractProperties(envelope.getOutputSnapshot()),
                 serializeAttributes(envelope.getAttributes()),
                 envelope.getTraceId(),
                 envelope.getSpanId(),
@@ -226,6 +228,16 @@ public class ChunkAccumulator {
         }
     }
 
+    private static String extractProperties(ExchangeSnapshot snapshot) {
+        if (snapshot == null || snapshot.getProperties() == null) return "";
+        try {
+            return MAPPER.writeValueAsString(snapshot.getProperties());
+        } catch (JsonProcessingException e) {
+            log.warn("Failed to serialize snapshot properties", e);
+            return "";
+        }
+    }
+
     private static String serializeAttributes(Map<String, String> attributes) {
         if (attributes == null || attributes.isEmpty()) {
             return "{}";

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

@@ -87,17 +87,21 @@ public class IngestionService {
         String outputBody = null;
         String inputHeaders = null;
         String outputHeaders = null;
+        String inputProperties = null;
+        String outputProperties = null;
 
         ExchangeSnapshot inputSnapshot = exec.getInputSnapshot();
         if (inputSnapshot != null) {
             inputBody = truncateBody(inputSnapshot.getBody());
             inputHeaders = toJson(inputSnapshot.getHeaders());
+            inputProperties = toJson(inputSnapshot.getProperties());
         }
 
         ExchangeSnapshot outputSnapshot = exec.getOutputSnapshot();
         if (outputSnapshot != null) {
             outputBody = truncateBody(outputSnapshot.getBody());
             outputHeaders = toJson(outputSnapshot.getHeaders());
+            outputProperties = toJson(outputSnapshot.getProperties());
         }
 
         boolean hasTraceData = hasAnyTraceData(exec.getProcessors());
@@ -118,6 +122,7 @@ public class IngestionService {
                 diagramHash,
                 exec.getEngineLevel(),
                 inputBody, outputBody, inputHeaders, outputHeaders,
+                inputProperties, outputProperties,
                 toJson(exec.getAttributes()),
                 exec.getErrorType(), exec.getErrorCategory(),
                 exec.getRootCauseType(), exec.getRootCauseMessage(),
@@ -153,6 +158,7 @@ public class IngestionService {
                     p.getErrorMessage(), p.getErrorStackTrace(),
                     truncateBody(p.getInputBody()), truncateBody(p.getOutputBody()),
                     toJson(p.getInputHeaders()), toJson(p.getOutputHeaders()),
+                    null, null, // inputProperties, outputProperties (not on ProcessorExecution)
                     toJson(p.getAttributes()),
                     null, null, null, null, null,
                     p.getResolvedEndpointUri(),

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

@@ -32,6 +32,8 @@ public record MergedExecution(
         String outputBody,
         String inputHeaders,
         String outputHeaders,
+        String inputProperties,
+        String outputProperties,
         String attributes,
         String traceId,
         String spanId,

cameleer3-server-core/src/main/java/com/cameleer3/server/core/storage/ExecutionStore.java

@@ -25,6 +25,7 @@ public interface ExecutionStore {
             String errorMessage, String errorStacktrace, String diagramContentHash,
             String engineLevel,
             String inputBody, String outputBody, String inputHeaders, String outputHeaders,
+            String inputProperties, String outputProperties,
             String attributes,
             String errorType, String errorCategory,
             String rootCauseType, String rootCauseMessage,
@@ -41,6 +42,7 @@ public interface ExecutionStore {
             Instant startTime, Instant endTime, Long durationMs,
             String errorMessage, String errorStacktrace,
             String inputBody, String outputBody, String inputHeaders, String outputHeaders,
+            String inputProperties, String outputProperties,
             String attributes,
             Integer loopIndex, Integer loopSize,
             Integer splitIndex, Integer splitSize,

cameleer3-server-core/src/test/java/com/cameleer3/server/core/detail/TreeReconstructionTest.java

@@ -27,7 +27,7 @@ class TreeReconstructionTest {
                 "exec-1", id, type,
                 "default", "route1", depth, parentId,
                 status, NOW, NOW, 10L,
-                null, null, null, null, null, null, null,
+                null, null, null, null, null, null, null, null, null,
                 null, null, null, null, null,
                 null, null, null, null, null, null, null, null,
                 null, null, null, null, null, null
@@ -118,7 +118,7 @@ class TreeReconstructionTest {
         return new ProcessorRecord(
                 "exec-1", id, type, "app", "route1",
                 0, null, status, NOW, NOW, 10L,
-                null, null, null, null, null, null, null,
+                null, null, null, null, null, null, null, null, null,
                 null, null, null, null, null,
                 null, null, null, null, null, null, null, null,
                 seq, parentSeq, iteration, iterationSize, null, null