feat: add Spotless and Ktlint plugins for code formatting and linting

[LMLiam]

📌 Summary

Adds Spotless and Ktlint to enforce code syntax

🔍 Related Issues / Tickets

• Closes chore: add Spotless for syntax enforcement #4

🛠 Changes in Detail

• Adds Spotless and Ktlint

🧩 Modules Affected

• spi-tooling-annotations
• spi-tooling-processor
• Other:

📦 Versioning

• Version bump applied (release PR)
• Snapshot only (PR build)

🧪 Testing

Not necessary

✅ Checklist

• Code builds locally without errors
• All tests pass locally (./gradlew kotest)
• Added/updated tests for new or changed logic
• Updated documentation / README if needed
• No unrelated changes included

📜 Notes for Reviewers

[github-actions]

🆕 PR Snapshot Published to Maven Central Snapshot Repository

You can test this PR build by adding the following dependencies:

Version: 0.1.21-PR10-1757009298-SNAPSHOT

implementation "io.github.eventhorizonlab:spi-tooling-annotations:0.1.21-PR10-1757009298-SNAPSHOT"
kapt "io.github.eventhorizonlab:spi-tooling-processor:0.1.21-PR10-1757009298-SNAPSHOT"

This comment will be updated automatically if a new snapshot is published for this PR