Add rolling-updates feature flag and compatibility framework

[ShashankFC]

Test 4

Summary by CodeRabbit

• New Features

  • Introduced Rolling Updates as a new preview feature for server maintenance operations.

• Documentation

  • Added configuration instructions for enabling Rolling Updates in operator and server environments.
  • Added caution notices indicating the Rolling Updates feature must be enabled for upgrade operations to proceed.

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Replicated from ai-code-review-evaluation/keycloak-coderabbit#4

[Copilot]

Pull request overview

This PR introduces a Rolling Updates feature flag and compatibility framework to enable controlled server upgrade strategies in Keycloak. The feature is marked as preview and requires explicit enablement through the rolling-updates feature flag.

Changes:

• Added ROLLING_UPDATES as a new preview feature in the Profile enum
• Implemented feature flag checks in update compatibility commands with a new exit code for disabled features
• Updated exit codes to align with picocli conventions, moving RECREATE_UPGRADE_EXIT_CODE from 4 to 3
• Updated documentation and configuration examples to require the rolling-updates feature flag

Reviewed changes

Copilot reviewed 10 out of 11 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
common/src/main/java/org/keycloak/common/Profile.java	Adds ROLLING_UPDATES as a new preview feature
quarkus/runtime/src/main/java/org/keycloak/quarkus/runtime/compatibility/CompatibilityResult.java	Updates exit codes and adds FEATURE_DISABLED constant
quarkus/runtime/src/main/java/org/keycloak/quarkus/runtime/cli/command/UpdateCompatibilityMetadata.java	Adds feature flag check before command execution
quarkus/runtime/src/main/java/org/keycloak/quarkus/runtime/cli/command/UpdateCompatibilityCheck.java	Adds feature flag check before command execution
quarkus/runtime/src/main/java/org/keycloak/quarkus/runtime/cli/command/AbstractUpdatesCommand.java	Adds method to print feature disabled error message
operator/src/test/java/org/keycloak/operator/testsuite/integration/UpgradeTest.java	Updates test to use FeatureSpec instead of UnsupportedSpec and enables rolling-updates
operator/scripts/Dockerfile-custom-image	Enables rolling-updates feature in build command
docs/guides/templates/kc.adoc	Updates template to include rolling-updates feature flag
docs/guides/server/update-compatibility.adoc	Adds documentation for new exit code 4 and feature requirement
docs/guides/operator/advanced-configuration.adoc	Adds caution notice and configuration example for enabling rolling-updates

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[Copilot]

The feature key will be derived as 'rolling_updates' (with underscore) but documentation and configuration examples use 'rolling-updates' (with hyphen). Consider renaming to 'ROLLING_UPDATES' to ensure the key matches the documented usage, or verify that the key transformation handles this correctly.

[Copilot]

Corrected grammar: 'Unable to use this command' should be 'This command cannot be used' or 'Unable to execute this command' for better clarity.

Suggested change

	printError("Unable to use this command. The preview feature 'rolling-updates' is not enabled.");
	printError("This command cannot be used. The preview feature 'rolling-updates' is not enabled.");