* fix(core): handle ExceptionGroup-wrapped ToolError and McpError in MCP tool execution
Fixes 3 related Datadog bugs (all fastmcp.exceptions.ToolError):
- 75d43daa-ff04-11f0-81b2-da7ad0900000
- 7af6373e-0080-11f1-9855-da7ad0900000
- a322edc8-fffa-11f0-b26c-da7ad0900000
These errors were caused by ToolError and McpError exceptions bubbling up
unhandled from the MCP REST endpoint. This fix combines the approaches from
PRs #9320 and #9321:
1. Handle ExceptionGroup wrapping (Python 3.11+ async TaskGroup)
2. Check for ToolError by class name to handle module variations
3. Convert ToolError to LettaInvalidArgumentError for proper client response
4. Catch McpError and return HTTP 500 with proper error message
Issue-IDs: 75d43daa-ff04-11f0-81b2-da7ad0900000, 7af6373e-0080-11f1-9855-da7ad0900000, a322edc8-fffa-11f0-b26c-da7ad0900000
🐾 Generated with [Letta Code](https://letta.com)
Co-Authored-By: Letta <noreply@letta.com>
* fix: return 422 instead of 500 for McpError (user config issue)
* fix: use LettaMCPConnectionError instead of HTTPException for McpError
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Co-authored-by: Letta <noreply@letta.com>
e7039470e9