fix: add artifact_full to --mcp-config flag allowlist

Without this, artifact_full runs generate the .mcp.json config file
and upload it to the container, but the --mcp-config flag is never
added to the claude CLI command. This causes the agent to fall back
to curl/WebFetch instead of using Sourcegraph MCP tools directly.

The mcp_type check for setting mcp_config_flag was missing
"artifact_full" despite the MCP setup function already handling it.

Validated: fixed run shows 39 direct MCP tool calls (0 curl/WebFetch)
vs broken run with 0 MCP calls (14 WebFetch + 19 curl).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: sjarmak

agents/claude_baseline_agent.py

@@ -715,7 +715,7 @@ def create_run_agent_commands(self, instruction: str) -> list[ExecInput]:
 
         # MCP configuration flag
         mcp_config_flag = ""
-        if mcp_type in ["sourcegraph", "sourcegraph_full", "sourcegraph_base", "sourcegraph_isolated", "deepsearch", "deepsearch_hybrid"]:
+        if mcp_type in ["sourcegraph", "sourcegraph_full", "sourcegraph_base", "sourcegraph_isolated", "artifact_full", "deepsearch", "deepsearch_hybrid"]:
             mcp_config_flag = "--mcp-config /logs/agent/sessions/.mcp.json "
 
         # Build disallowed tools list (blocks local search to force MCP usage)