Move PlantUML diagrams to assets folder for better organization

[Copilot]

This PR moves the PlantUML diagrams from the root /diagrams folder to /assets/diagrams to reduce clutter and improve repository organization.

Changes Made

• Moved entire /diagrams folder to /assets/diagrams including:

  • README.md with PlantUML setup instructions
  • src/ directory containing .puml source files
  • out/ directory containing generated SVG diagrams

• Updated VS Code settings in .vscode/settings.json:

  • plantuml.diagramsRoot: diagrams/src → assets/diagrams/src
  • plantuml.exportOutDir: diagrams/out → assets/diagrams/out

• Updated example configuration in the diagrams README.md to reflect the new paths

Verification

• All PlantUML source files (.puml) and generated outputs (.svg) remain intact
• VS Code PlantUML extension configuration updated to work with new paths
• No other code references to old paths exist in the codebase
• All existing tests continue to pass (108/108 tests passing)

The diagrams functionality remains fully operational with the new folder structure.

Fixes #28.

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[github-actions]

Python 3.13 Test Results

108 tests  ±0   108 ✅ ±0   1s ⏱️ -1s
  1 suites ±0     0 💤 ±0 
  1 files   ±0     0 ❌ ±0 

Results for commit f631dcf. ± Comparison against base commit 063f570.

♻️ This comment has been updated with latest results.

[github-actions]

Python 3.12 Test Results

108 tests  ±0   108 ✅ ±0   1s ⏱️ -1s
  1 suites ±0     0 💤 ±0 
  1 files   ±0     0 ❌ ±0 

Results for commit f631dcf. ± Comparison against base commit 063f570.

♻️ This comment has been updated with latest results.