7167 : fix classDef style application for treemap diagramtype

[omkarht]

📑 Summary

This PR fixes the classDef style application mechanism in treemap diagrams. Previously, user-defined styles via classDef were not being applied correctly due to type inconsistencies and SVG attribute override issues. This fix ensures that treemap diagrams now properly respect custom styles defined through classDef, bringing them in line with other diagram types like flowchart and state diagrams.

Resolves #7167

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Latest commit: 1aa4cd9

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commit: 1aa4cd9

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 3.55%. Comparing base (2346801) to head (1aa4cd9).
⚠️ Report is 5 commits behind head on develop.

Files with missing lines	Patch %	Lines
packages/mermaid/src/diagrams/treemap/parser.ts	0.00%	1 Missing ⚠️
packages/mermaid/src/diagrams/treemap/utils.ts	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #7178   +/-   ##
=======================================
  Coverage     3.55%   3.55%           
=======================================
  Files          473     473           
  Lines        47500   47500           
  Branches       731     731           
=======================================
  Hits          1687    1687           
  Misses       45813   45813           

Flag	Coverage Δ
unit	3.55% <0.00%> (ø)

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Files with missing lines	Coverage Δ
packages/mermaid/src/diagrams/treemap/parser.ts	0.00% <0.00%> (ø)
packages/mermaid/src/diagrams/treemap/utils.ts	2.56% <0.00%> (ø)

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Build	Status	Details	Updated (UTC)
default (Inspect)	👍 Changes approved	4 changed, 5 added	Nov 27, 2025, 7:14 AM

[sidharthv96]

Does the argos changes validate this fix?

[omkarht]

Does the argos changes validate this fix?

Yes @sidharthv96 , the Argos results validate the fix. I’ve also added 5 additional test cases to ensure broader coverage and confirm the behaviour.