We should allow an option to record an mcp-scan proxy session into a trace.json file or push it (via Append API), directly to https://explorer.invariantlabs.ai.

mcp-scan proxy --record trace.json

should record the ongoing MCP session trace into a local file.

mcp-scan proxy --record explorer:dataset

should record the ongoing MCP session trace into a new trace in 'dataset' on explorer.invariantlabs.ai. API key and endpoint (e.g. Explorer instance), can just be specified via environment variable, if we use the standard Invariant SDK for upload.