fix(architecture): expand group bounding box to include child sizes (fix #7175)

[kdy10091009]

📑 Summary

Fixes #7175 — group boxes in architecture diagrams could overlap or not expand correctly when group names are long or children have wide rendered sizes. This patch changes how group bounding boxes are computed so the group rectangle is derived from children's rendered widths/heights (when available) plus padding.

Resolves #7175

📏 Design Decisions

• Calculate group bounding box from rendered child element sizes when available:
  • For each child, prefer element.node().getBBox() (via db.getElementById(id)) and fall back to cytoscape child data width/height.
  • Aggregate min/max left/top/right across children and then apply configured padding.
• If a group has no children, fall back to cy.boundingBox() as before.
• Preserve existing offsets used for icons/labels and keep label/icon placement behavior.
• Keep changes minimal and focused to drawGroups in packages/mermaid/src/diagrams/architecture/svgDraw.ts.

📋 Tasks

• 📖 Read the contribution guidelines.
• 💻 Added unit tests to cover the drawGroups behavior (packages/mermaid/src/diagrams/architecture/svgDraw.spec.ts).
• 💻 Added an E2E image snapshot for the group-sizing rendering (cypress/integration/rendering/architecture-group-sizing.spec.js).
• 📓 If maintainers want documentation updates, I can add or update docs (not required for this bug fix).
• 🦋 No changeset added — please advise if you want a changeset for release notes; I can add one (pnpm changeset).

Files changed (high level)

• Modified: packages/mermaid/src/diagrams/architecture/svgDraw.ts — compute group bbox from children + padding
• Added: packages/mermaid/src/diagrams/architecture/svgDraw.spec.ts — TypeScript unit tests (mocking createText to avoid heavy DOM emulation)
• Added: cypress/integration/rendering/architecture-group-sizing.spec.js — E2E image snapshot test

Local verification

• Ran full unit test suite locally:
  • pnpm test — All unit tests passed locally (Test Files 104 passed | 1 skipped; Tests 3684 passed | 12 skipped | 2 todo).
• Note: I did not run the full Cypress suite locally (it is slow and depends on dev server availability). The E2E snapshot test is included in this PR and will run in CI.

CI notes & follow-ups

• codecov: If codecov reports missing coverage, I can add more focused unit tests to hit additional branches in drawGroups.
• Argos / visual diffs: The E2E image snapshot may produce visual diffs in Argos; if intended, the maintainers should approve updated snapshots in the visual regression tool.

If you'd like, I can:

• Add a changeset and update this PR accordingly.
• Run a targeted Cypress spec locally (I can start a dev server and run only the new spec).
• Add more unit tests to cover further edge cases.

Thanks! Please let me know which follow-up you'd prefer.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 5c9e8ec

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commit: 5c9e8ec

[codecov]

Codecov Report

❌ Patch coverage is 0% with 57 lines in your changes missing coverage. Please review.
✅ Project coverage is 3.54%. Comparing base (b1fe4ff) to head (5c9e8ec).

Files with missing lines	Patch %	Lines
...kages/mermaid/src/diagrams/architecture/svgDraw.ts	0.00%	57 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           develop   #7190      +/-   ##
==========================================
- Coverage     3.55%   3.54%   -0.01%     
==========================================
  Files          473     473              
  Lines        47500   47556      +56     
  Branches       731     731              
==========================================
  Hits          1687    1687              
- Misses       45813   45869      +56     

Flag	Coverage Δ
unit	3.54% <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
...kages/mermaid/src/diagrams/architecture/svgDraw.ts	0.28% <0.00%> (-0.06%)	⬇️

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Build	Status	Details	Updated (UTC)
default (Inspect)	⚠️ Changes detected (Review)	1 changed, 1 added	Nov 24, 2025, 12:46 AM