refactor: stabilize selector preview cards

[lyzno1]

Summary

• 3c58326960 moves model selector preview state to one shared detached PreviewCard so selection no longer drops the preview anchor.
• b32cad8d17 gives the model selector popup the default settings width to remove the LLM panel horizontal overflow.
• 1bb69a9d1f applies the same shared PreviewCard handle/payload model to block selector nodes, tools, triggers, and featured marketplace rows.

Tests

• pnpm test app/components/workflow/block-selector
• pnpm type-check
• git diff --check

[codecov]

Codecov Report

❌ Patch coverage is 70.70707% with 29 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.87%. Comparing base (d110112) to head (af3d52a).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...tting/model-provider-page/model-selector/popup.tsx	55.00%	9 Missing ⚠️
...omponents/workflow/block-selector/start-blocks.tsx	66.66%	5 Missing ⚠️
...ents/workflow/block-selector/featured-triggers.tsx	75.00%	3 Missing ⚠️
...w/block-selector/rag-tool-recommendations/list.tsx	0.00%	3 Missing ⚠️
...ts/workflow/block-selector/trigger-plugin/item.tsx	57.14%	3 Missing ⚠️
.../app/components/workflow/block-selector/blocks.tsx	81.81%	2 Missing ⚠️
...ponents/workflow/block-selector/featured-tools.tsx	80.00%	2 Missing ⚠️
...nents/workflow/block-selector/tool/action-item.tsx	75.00%	1 Missing ⚠️
...flow/block-selector/trigger-plugin/action-item.tsx	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #36105      +/-   ##
==========================================
- Coverage   85.88%   85.87%   -0.01%     
==========================================
  Files        4456     4456              
  Lines      210920   210959      +39     
  Branches    39446    39449       +3     
==========================================
+ Hits       181144   181162      +18     
- Misses      26552    26573      +21     
  Partials     3224     3224              

Flag	Coverage Δ
dify-ui	94.40% <ø> (ø)
web	86.60% <70.70%> (-0.02%)	⬇️

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