Modularize MCP server by implementing tool definitions, stateless req…

[cstns]

Description

Fills in the MCP server route shell from #7426 with the actual endpoint handler. External AI agents can now connect to POST /api/v1/mcp and get real MCP protocol responses.

• Stateless Streamable HTTP: fresh McpServer and transport per request, no sessions, cleanup after each request
• Auth token forwarded to existing routes via app.inject(), so all middleware, validation, and RBAC runs as-is
• Tool registration framework that auto-discovers tool files from a tools/ directory
• Stub scope check ready for scoped PATs (Add PAT (Personal Acces Tokens) scopes #7411)
• Ships with two team tools (list-teams, get-team) to prove the plumbing end-to-end
• formatResponse helper converts inject responses to MCP CallToolResult, including error propagation
• Polyfill for socket.destroySoon to handle Fastify's mock sockets in test/inject path

Builds on #7426. Tool definitions for the remaining domains (applications, instances, snapshots, devices, catalog, navigation) are tracked in #7430.

Related Issue(s)

closes #7429

Checklist

• I have read the contribution guidelines
• Suitable unit/system level tests have been added and they pass
• Documentation has been updated
  • Upgrade instructions
  • Configuration details
  • Concepts
• Changes flowforge.yml?
  • Issue/PR raised on FlowFuse/helm to update ConfigMap Template
  • Issue/PR raised on FlowFuse/CloudProject to update values for Staging/Production
• Link to Changelog Entry PR, or note why one is not needed.

Labels

• Includes a DB migration? -> add the area:migration label

[codecov]

Codecov Report

❌ Patch coverage is 98.11321% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 77.03%. Comparing base (6b598c8) to head (12c443d).

Files with missing lines	Patch %	Lines
forge/ee/routes/mcp/toolLoader.js	96.29%	1 Missing ⚠️

Additional details and impacted files

@@                   Coverage Diff                    @@
##           7426_mcp-scaffolding    #7598      +/-   ##
========================================================
+ Coverage                 76.97%   77.03%   +0.05%     
========================================================
  Files                       412      414       +2     
  Lines                     21101    21153      +52     
  Branches                   5141     5145       +4     
========================================================
+ Hits                      16243    16295      +52     
  Misses                     4858     4858              

Flag	Coverage Δ
backend	77.03% <98.11%> (+0.05%)	⬆️

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