MCP Track B Phase B5-B6: enable governed group/public tools and enterprise readiness

[Bionic711]

Summary

Complete the deferred inbound MCP scope from #1013: governed group/public/all-scope tools plus enterprise-readiness hardening.

Deferred Tools

Keep these disabled until this issue is implemented and explicitly reviewed:

• list_group_workspaces
• list_group_documents
• list_group_prompts
• list_public_workspaces
• list_public_documents
• list_public_prompts
• All-scope search_documents
• All-scope send_chat_message

Scope

• Reuse existing group/public role checks and workspace-status checks.
• Add governance controls per tool and scope.
• Add tenant/client/user audit logging.
• Add pagination and result limits.
• Add negative tests for users without workspace access.
• Add admin UX for enabling specific tools/scopes rather than relying on environment variables.
• Add correlation IDs across MCP requests, tool execution, and downstream SimpleChat operations.
• Track caller app ID, delegated user ID, tool name, duration, result status, and error type.
• Redact tokens, secrets, prompts, and sensitive document content.
• Avoid in-memory token/session caches as production state.
• Add bounded request timeouts, safe retry behavior, and health/readiness endpoints.
• Ensure multi-instance deployments behave consistently.
• Document app registration, PRM metadata, inbound MCP governance setup, supported tools, non-goals, and disablement workflows.

Acceptance Criteria

• Group/public/all-scope tools remain disabled until explicitly enabled by governance.
• Users without workspace roles cannot access group/public data.
• Inactive or disabled workspaces remain blocked.
• Admin UX supports client/tool/scope enablement and redaction.
• Audit and telemetry identify caller app, delegated user, tool, duration, status, and error type without logging secrets.
• Health/readiness endpoints work for the MCP hosting surface.
• Multi-instance behavior does not rely on in-memory auth state.
• Documentation covers setup, governance, supported tools, and operational disablement.

Notes

Parent: #1013
Depends on the inbound auth/governance foundation and initial personal tool issues.
Planning doc: docs/explanation/features/MCP_PLUGIN_ROBUSTNESS_PLAN.md
Priority: P1
Size: XL