fix: Node and edge labels should only render as markdown if properly delimited

[ajuckel]

📑 Summary

Restores the behavior that only nodes and edges delimited with double-quote-backtick (e.g. node["`_markdown_ **text**`"]) are processed as markdown.

Resolves #6275, #6048, and #5824

📏 Design Decisions

The implementation is based on #6087. First, I simply rebased on top of develop and resolved the conflicts as seemed appropriate to me.

Intentional changes:

• Updated the node test from node.labelType !== 'string' to node.labelType === 'markdown'.
• After looking through the e2e tests, I assumed 'string' was used to resolve some of the iconShape e2e tests. To resolve, I made the label default 'markdown' for nodes built from NodeMetaData, and added the capability to configure it via an additional labelType key.

If this is a more acceptable fix for the linked issues, this would replace my alternate PR #6277.

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🦋 Changeset detected

Latest commit: 119daa3

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

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commit: 119daa3

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 52 lines in your changes missing coverage. Please review.

Project coverage is 3.85%. Comparing base (d602240) to head (119daa3).

Files with missing lines	Patch %	Lines
...c/rendering-util/rendering-elements/shapes/util.ts	0.00%	18 Missing ⚠️
packages/mermaid/src/diagrams/flowchart/flowDb.ts	0.00%	14 Missing ⚠️
.../src/rendering-util/rendering-elements/clusters.js	0.00%	11 Missing ⚠️
...aid/src/rendering-util/rendering-elements/edges.js	0.00%	9 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           develop   #6345      +/-   ##
==========================================
- Coverage     3.86%   3.85%   -0.01%     
==========================================
  Files          402     402              
  Lines        42682   42716      +34     
  Branches       644     644              
==========================================
  Hits          1648    1648              
- Misses       41034   41068      +34     

Flag	Coverage Δ
unit	3.85% <0.00%> (-0.01%)	⬇️

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

Files with missing lines	Coverage Δ
packages/mermaid/src/diagrams/flowchart/types.ts	100.00% <ø> (ø)
packages/mermaid/src/types.ts	100.00% <ø> (ø)
...aid/src/rendering-util/rendering-elements/edges.js	0.00% <0.00%> (ø)
.../src/rendering-util/rendering-elements/clusters.js	0.00% <0.00%> (ø)
packages/mermaid/src/diagrams/flowchart/flowDb.ts	0.00% <0.00%> (ø)
...c/rendering-util/rendering-elements/shapes/util.ts	0.00% <0.00%> (ø)

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Build	Status	Details	Updated (UTC)
default (Inspect)	⚠️ Changes detected (Review)	791 changed, 3 added, 12 removed, 12 failures	Mar 20, 2025, 9:07 PM