fix: MCP connection refresh state

[erichare]

Summary

• Add an MCP server refresh action on the MCP node parameter control.
• Force backend MCP tool reloads when refresh is requested, bypassing stale options/cache and surfacing the concrete connection error in the tool placeholder.
• Clear stale frontend error status after successful MCP template refreshes and show selected server errors directly in the node UI.

Root Cause

MCP server/tool refreshes could reuse existing dropdown options or cache entries, so a node that had previously failed could keep stale frontend error state even after the backend had successfully refreshed the server configuration. Error placeholders also collapsed connection failures into generic text.

Validation

• uv run pytest src/backend/tests/unit/components/models_and_agents/test_mcp_component_dynamic.py -q
• npm test -- McpComponent.test.tsx --runInBand
• npm run lint:types -- src/components/core/parameterRenderComponent/components/mcpComponent/index.tsx src/components/core/parameterRenderComponent/components/mcpComponent/__tests__/McpComponent.test.tsx
• uv run ruff format src/lfx/src/lfx/components/models_and_agents/mcp_component.py src/backend/tests/unit/components/models_and_agents/test_mcp_component_dynamic.py --check
• pre-commit hooks via uv run git commit

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✨ Finishing Touches

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• Create PR with unit tests
• Commit unit tests in branch fix/mcp-connection-refresh-state

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[codecov]

Codecov Report

❌ Patch coverage is 95.23810% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 54.12%. Comparing base (e68e33e) to head (3bdb73d).
⚠️ Report is 1 commits behind head on release-1.10.0.

Files with missing lines	Patch %	Lines
...rRenderComponent/components/mcpComponent/index.tsx	94.65%	7 Missing ⚠️

Additional details and impacted files

@@                 Coverage Diff                 @@
##           release-1.10.0   #12931       +/-   ##
===================================================
+ Coverage           41.71%   54.12%   +12.41%     
===================================================
  Files                1909     2051      +142     
  Lines              175706   188193    +12487     
  Branches            10132    27910    +17778     
===================================================
+ Hits                73297   101864    +28567     
+ Misses             101298    85217    -16081     
- Partials             1111     1112        +1     

Flag	Coverage Δ
backend	57.12% <ø> (+1.95%)	⬆️
frontend	54.42% <95.23%> (+18.20%)	⬆️
lfx	49.76% <ø> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...controllers/API/queries/mcp/use-get-mcp-servers.ts	69.90% <100.00%> (+69.90%)	⬆️
...rRenderComponent/components/mcpComponent/index.tsx	86.14% <94.65%> (+86.14%)	⬆️

... and 1176 files with indirect coverage changes

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[github-actions]

Frontend Unit Test Coverage Report

Coverage Summary

Lines	Statements	Branches	Functions
	36.44% (42454/116484)	67.67% (5819/8598)	36.25% (973/2684)

Unit Test Results

Tests	Skipped	Failures	Errors	Time
4097	0 💤	0 ❌	0 🔥	8m 56s ⏱️

[Cristhianzl]

lgtm