Add dash0 plugin (#1641)

.claude-plugin/marketplace.json

@@ -611,6 +611,20 @@
       "category": "productivity",
       "homepage": "https://claude.com/cwc-makers"
     },
+    {
+      "name": "dash0",
+      "description": "OpenTelemetry observability for Claude Code sessions. Captures tool calls, LLM invocations, token usage, and errors as OTel traces. Send telemetry to Dash0 or any OpenTelemetry-compatible backend.",
+      "author": {
+        "name": "Dash0"
+      },
+      "category": "monitoring",
+      "source": {
+        "source": "url",
+        "url": "https://github.com/dash0hq/dash0-agent-plugin.git",
+        "sha": "38c6d74e637bd7dbe1fa2c364de66d07efe88a9a"
+      },
+      "homepage": "https://dash0.com/"
+    },
     {
       "name": "data",
       "description": "Data engineering for Apache Airflow and Astronomer. Author DAGs with best practices, debug pipeline failures, trace data lineage, profile tables, migrate Airflow 2 to 3, and manage local and cloud deployments.",