fix: prevent workflow preview resize observer loop

[lyzno1]

Summary

• Debounced workflow canvas, right panel, and bottom panel size writes with requestAnimationFrame to break the resize feedback loop that was triggering the dev overlay.
• Added equality checks in the workflow layout store so repeated size values no longer emit redundant updates.
• Aligned the panel resize hook to a fixed callback-only signature and removed the extra dependency spread.
• Updated the workflow panel/operator tests to cover the async resize flow.

Testing

• pnpm type-check
• pnpm test --run app/components/workflow/panel/__tests__/index.spec.tsx app/components/workflow/operator/__tests__/index.spec.tsx app/components/workflow/store/workflow/__tests__/layout-slice.spec.ts app/components/workflow/store/__tests__/workflow-store.spec.ts
• Chrome UI verification: reopened the workflow preview panel and confirmed the ResizeObserver overlay no longer appears.

[codecov]

Codecov Report

❌ Patch coverage is 75.34247% with 18 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.82%. Comparing base (cb0356e) to head (9497f7b).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
web/app/components/workflow/index.tsx	25.00%	12 Missing ⚠️
web/app/components/workflow/operator/index.tsx	75.00%	4 Missing ⚠️
web/app/components/workflow/panel/index.tsx	90.47%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #35936      +/-   ##
==========================================
- Coverage   85.83%   85.82%   -0.01%     
==========================================
  Files        4461     4461              
  Lines      209224   209273      +49     
  Branches    39168    39186      +18     
==========================================
+ Hits       179583   179614      +31     
- Misses      26466    26484      +18     
  Partials     3175     3175              

Flag	Coverage Δ
dify-ui	94.23% <ø> (ø)
web	86.75% <75.34%> (-0.02%)	⬇️

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