Fix Device based MCP error log in app log

[Steve-Mcl]

Description

• add missing await to DB call
• skip querying devices MCP tools (other parts of feature not ready yet)
• dont permit invalid instances or types into the MCP Registrations
• tests to prevent regression

Tests added

▼ MCP Server Registration
  ✔ should return 500 and log error for unknown device
  ✔ should return 500 and log error for unknown instance
  ✔ should return 500 and log error for unknown type

Related Issue(s)

closes #6586

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

[hardillb]

Needs tests fixing

[Steve-Mcl]

Needs tests fixing

Nice - the new logic to prevent invalid instances being added to MCPRegistrations table highlighted some bad unit tests - should be good now!

[hardillb]

Will let the tests pass, but also not merging until other problems are fixed

[codecov]

Codecov Report

❌ Patch coverage is 87.50000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 76.66%. Comparing base (4bef29b) to head (5c285e8).
⚠️ Report is 10 commits behind head on main.

Files with missing lines	Patch %	Lines
forge/routes/api/expert.js	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6587      +/-   ##
==========================================
+ Coverage   76.61%   76.66%   +0.04%     
==========================================
  Files         398      398              
  Lines       20100    20103       +3     
  Branches     4839     4841       +2     
==========================================
+ Hits        15400    15411      +11     
+ Misses       4700     4692       -8     

Flag	Coverage Δ
backend	76.66% <87.50%> (+0.04%)	⬆️

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[Steve-Mcl]

@hardillb the strictness of PG was overlooked (didnt like made up instance id xxxx-xxx-xxx) fixed last test in fix test for strict PG (should be valid UUID)

Good to go now