Improve devtools statechart layout

[SandroMaglione]

Summary

• make the static statechart follow a stable left-to-right order, reduce edge crossings, and reserve clear routes for reverse and self-transitions
• distinguish automatic transitions and invoke outcomes through line styles and muted activity-specific colors
• organize parallel regions and states without a statically known path into separate areas
• add an Analysis inspector for declared public events without handlers and state subtrees without a statically known path from the initial configuration

Changeset

• Added or updated for a library or package-metadata change
• Not required because this PR does not change a publishable package

Validation

• pnpm check
• Automated type-performance measurement passed or was not required
• Automated runtime- and memory-performance measurement passed or was not required

The local runtime benchmark completed as a functional smoke test. This change does not affect the public TypeScript API, so a local type-performance run was not required.