6806: Adding support for the new use-case diagram type

[omkarht]

📑 Summary

Adding support for the new use-case diagram type

Resolves #6806

📏 Design Decisions

📋 Tasks

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• 📖 have read the contribution guidelines
• 💻 have added necessary unit/e2e tests.
• 📓 have added documentation. Make sure MERMAID_RELEASE_VERSION is used for all new features.
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Latest commit: b715d82

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commit: b715d82

[codecov]

Codecov Report

❌ Patch coverage is 0.78883% with 1635 lines in your changes missing coverage. Please review.
✅ Project coverage is 3.46%. Comparing base (c728d86) to head (b715d82).
⚠️ Report is 124 commits behind head on develop.

Files with missing lines	Patch %	Lines
packages/parser/src/language/usecase/visitor.ts	0.18%	532 Missing ⚠️
packages/mermaid/src/diagrams/usecase/usecaseDb.ts	0.00%	276 Missing ⚠️
.../src/rendering-util/rendering-elements/clusters.js	0.00%	147 Missing ⚠️
...util/rendering-elements/shapes/usecaseActorIcon.ts	0.00%	101 Missing ⚠️
...ing-util/rendering-elements/shapes/usecaseActor.ts	0.00%	100 Missing ⚠️
packages/parser/src/language/usecase/parser.ts	1.00%	99 Missing ⚠️
...ages/mermaid/src/diagrams/usecase/usecaseParser.ts	1.01%	98 Missing ⚠️
.build/antlr-cli.ts	1.85%	53 Missing ⚠️
...endering-util/rendering-elements/shapes/ellipse.ts	0.00%	45 Missing ⚠️
packages/mermaid/src/diagrams/usecase/styles.ts	0.00%	29 Missing ⚠️
... and 18 more

Additional details and impacted files

@@            Coverage Diff             @@
##           develop   #7081      +/-   ##
==========================================
- Coverage     3.55%   3.46%   -0.10%     
==========================================
  Files          473     492      +19     
  Lines        47454   49127    +1673     
  Branches       730     749      +19     
==========================================
+ Hits          1687    1700      +13     
- Misses       45767   47427    +1660     

Flag	Coverage Δ
unit	3.46% <0.78%> (-0.10%)	⬇️

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

Files with missing lines	Coverage Δ
packages/mermaid/src/config.type.ts	100.00% <ø> (ø)
packages/mermaid/src/defaultConfig.ts	41.31% <100.00%> (+0.55%)	⬆️
packages/mermaid/src/diagrams/flowchart/flowDb.ts	0.00% <ø> (ø)
.build/jsonSchema.ts	0.00% <0.00%> (ø)
packages/parser/src/language/index.ts	0.00% <0.00%> (ø)
.esbuild/build.ts	0.00% <0.00%> (ø)
.vite/build.ts	0.86% <0.00%> (-0.02%)	⬇️
packages/examples/src/index.ts	2.08% <0.00%> (-0.10%)	⬇️
...s/mermaid/src/diagram-api/diagram-orchestration.ts	0.00% <0.00%> (ø)
.build/generateAntlr.ts	0.00% <0.00%> (ø)
... and 21 more

... and 3 files with indirect coverage changes

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Build	Status	Details	Updated (UTC)
default (Inspect)	⚠️ Changes detected (Review)	27 added	Oct 15, 2025, 7:28 AM