Migrate to Vaadin 25, Spring Boot 4, and Spring AI 2.0

[manolo]

Summary

• Upgrade Vaadin from 24.x to 25.0.0-beta9
• Upgrade Spring Boot from 3.x to 4.0.0
• Upgrade Spring AI from 1.x to 2.0.0-SNAPSHOT
• Fix breaking changes introduced by these upgrades

Changes

Dependencies (pom.xml)

• Bump vaadin.version to 25.0.0-beta9
• Bump spring-boot-starter-parent to 4.0.0
• Bump spring.ai.version to 2.0.0-SNAPSHOT
• Add vaadin-dev dependency (required in V25)
• Add central-portal-snapshots repository for MCP SDK
• Exclude Jackson 2 dependencies from Spring AI to avoid conflicts with Vaadin's Jackson 3

Code fixes

• MainLayout.java: Update AfterNavigationEvent API usage (changed in V25)
• ComponentsView.java: Workaround for Charts bug with dynamic DataSeries.add() (see vaadin/flow-components#XXXX)

Frontend

• Regenerate package.json, package-lock.json, and tsconfig.json for V25

Notes

• Spring AI 2.0.0-SNAPSHOT is required for Spring Boot 4 compatibility
• There's a known bug in Charts 25.0.0-beta9 with dynamic data updates (reported separately)