[Epic] Build a unified tool and knowledge layer #17

Problem

The control plane needs one tracked epic for tool federation, repo intelligence, attachments, and auditable tool use.

Scope

• Track MCPGateway integration, MCP registry UX, built-in tools, RagSharp integration, attachments, and auditability
• Keep tool discovery and invocation visible and governed

Out of scope

• Git implementation details outside the tool layer
• Provider-specific setup that belongs in the Toolchain Center

Planned child issues

• Integrate ManagedCode.MCPGateway as the shared tool catalog
• Build the MCP registry UI
• Add first-party built-in tools and attachment ingestion
• Integrate RagSharp and implement tool-call audit plus replay

Definition of Done

• The tool and knowledge issues exist and reference this epic
• The epic makes auditability a first-class requirement

Verification

• Child issues reference this epic
• The epic preserves a clean boundary between provider setup and tool federation