build(server): migrate Java formatting to Spotless

[FelixTJDietrich]

Description

Migrates Java formatting from prettier-plugin-java to Maven-native Spotless with Palantir Java Format. This removes Java's Node-based formatting path, keeps generated clients outside the formatter scope, and makes Maven verify enforce the complete handwritten application tree.

This builds on #1529, which introduced the application/generated-client module boundary and has now merged.

What changed

• pins Spotless 3.10.1 and Palantir Java Format 2.97.0 in Maven;
• binds spotless:check to Maven verify for application main and test sources;
• explicitly stores Spotless's local timestamp index at application/target/spotless-index;
• preserves the public pnpm run format, format:check, and check commands;
• removes the Java Prettier plugin, its configuration, and the now-unused process wrapper;
• documents the canonical commands and official IntelliJ/Eclipse integrations;
• reformats 2,413 handwritten Java files in a separate mechanical commit; and
• records that mechanical commit in .git-blame-ignore-revs.

Generated clients are excluded structurally by configuring Spotless only in the application module. No import sorting, unused-import removal, ratcheting, or semantic cleanup is included.

Performance

On the same warm local checkout used for the migration audit:

Check	Before	After
Java formatting	28.78 s	3.02 s
Complete pnpm run check	53.18 s	34.25 s

The warm Spotless check used its explicit local index. CI does not cache that index.

Fixes #1464

How to test

• pnpm run format
• pnpm run check
• pnpm run test:server:unit — 6,784 tests passed
• ran spotless:apply twice and confirmed the second run was byte-idempotent
• planted a Java formatting violation and confirmed both spotless:check and Maven verify rejected it
• confirmed the existing Unicode/NUL fixtures format successfully
• compared generated-client Java hashes before and after formatting; they were unchanged

Checklist

• The changeset is intentionally empty because this changes development and CI tooling only.
• No operator action or migration is required.

[coderabbitai]

Important

Review skipped

Auto reviews are disabled on base/target branches other than the default branch.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: bbe6149b-c1e7-4ea9-a937-3b964b26730f

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[coderabbitai]

Caution

CodeRabbit couldn't update its existing comment. The review summary may be out of date.

Error details

Validation Failed: {"resource":"IssueComment","code":"custom","field":"body","message":"body is too long (maximum is 65536 characters)"} - https://docs.github.com/rest/issues/comments#update-an-issue-comment

[coderabbitai]

Caution

CodeRabbit couldn't update its existing comment. The review summary may be out of date.

Error details

Validation Failed: {"resource":"IssueComment","code":"custom","field":"body","message":"body is too long (maximum is 65536 characters)"} - https://docs.github.com/rest/issues/comments#update-an-issue-comment

[github-actions]

📚 Documentation Preview

Preview has been removed (PR closed)

[coderabbitai]

Caution

CodeRabbit couldn't update its existing comment. The review summary may be out of date.

Error details

Validation Failed: {"resource":"IssueComment","code":"custom","field":"body","message":"body is too long (maximum is 65536 characters)"} - https://docs.github.com/rest/issues/comments#update-an-issue-comment

[coderabbitai]

Caution

CodeRabbit couldn't update its existing comment. The review summary may be out of date.

Error details

Validation Failed: {"resource":"IssueComment","code":"custom","field":"body","message":"body is too long (maximum is 65536 characters)"} - https://docs.github.com/rest/issues/comments#update-an-issue-comment

[coderabbitai]

Caution

CodeRabbit couldn't update its existing comment. The review summary may be out of date.

Error details

Validation Failed: {"resource":"IssueComment","code":"custom","field":"body","message":"body is too long (maximum is 65536 characters)"} - https://docs.github.com/rest/issues/comments#update-an-issue-comment