MCP compatibility for AI agents: server registry, JSON-RPC client, gateway, run-time tool catalog

Agents can now use Model Context Protocol servers. End to end:
- SharedKernel seam IMcpGateway (ListToolsAsync / CallToolAsync) + McpToolDescriptor / McpToolResult,
  so the Assembler discovers and can invoke MCP tools without referencing Integrations' tables.
- Integrations: McpServerConfig (org-scoped, owner-only; auth headers AES-GCM encrypted, never
  returned — only their names) + AddMcpServers migration. McpClient: a dependency-free Streamable-HTTP
  JSON-RPC 2.0 client (initialize → notifications/initialized → tools/list / tools/call), carrying the
  Mcp-Session-Id and parsing both application/json and text/event-stream replies. McpGateway resolves
  an org's servers, decrypts headers server-side, and is best-effort: an unreachable server is logged
  and skipped, never failing the run. CRUD + connectivity-test endpoints (create/test/delete owner-only
  via ManageApiKeys; list via ConfigureAgents to bind).
- OrgBoard: Agent gains McpServerIds (uuid[]; migration backfills existing agents to empty) flowing
  through ConfigureAgent + AgentRunContext.
- Assembler: AgentRunExecutor lists the agent's MCP tools (best-effort) and PromptAssembler renders a
  "# Tools (MCP)" catalog — labelled as data, never instructions — and records it in the run trace.
- Client: SeatsPage gains an MCP servers card (add/test/delete, encrypted auth header) and a per-agent
  MCP server multi-select; api client gains del().

Note: discovery + the governed call gateway are in place now; the autonomous model-driven tool-call
loop (model emits tool_calls → gated execution → feedback) needs a tool-calling model client and is
the next increment — the stub model can't drive it.

Verified: ArchitectureTests 8/8, IntegrationTests 53/53 (McpClientTests: JSON-RPC handshake/session,
json + SSE; McpServerRegistryTests: owner-only, encrypted-header-never-returned, graceful test,
Member 403; PromptAssemblerMcpTests: catalog + trace, omitted when empty), client build green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/Modules/TeamUp.Modules.OrgBoard/Runtime/AgentRunContextProvider.cs

@@ -29,7 +29,7 @@ internal sealed class AgentRunContextProvider(OrgBoardDbContext db) : IAgentRunC
 
         return new AgentRunContext(
             seatId, agent.Id, agent.Name, agent.Monogram, agent.Autonomy,
-            agent.ApiConfigId, agent.FallbackApiConfigId, agent.SkillKeys, agent.Docs,
+            agent.ApiConfigId, agent.FallbackApiConfigId, agent.SkillKeys, agent.McpServerIds, agent.Docs,
             item.Id, item.Title, item.Description, item.Type.ToString(),
             team.Id, team.OrganizationId);
     }