fix: align Spring Boot version property and adoption checklist with Java 26 and Boot 4.1.1

[SatyamPandey-07]

PR: fix: align Spring Boot version property and adoption checklist with Java 26 and Boot 4.1.1

Related Issue

Fixes #2651

Changes Proposed

• [pom.xml]: Synchronized <spring-boot.version> from 4.0.3 to 4.1.1 to match spring-boot-starter-parent.
• [docs/SPRING_BOOT_4_ADOPTION_CHECKLIST.md]: Updated baseline versions to accurately reflect the current project state (Spring Boot 4.1.1, Java 26, and Spring Cloud 2025.1.3).

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

• Verified POM XML consistency and property alignment
• Verified ./scripts/validate-versions.sh passes successfully

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings

[commjoen]

Thank you for your contribution @SatyamPandey-07 !