fix: emit task process type in release YAML for cf run-task support

[stokpop]

Summary

• cf run-task failed with "command presence FAILED" on Go buildpack v5
  while working on Ruby buildpack v4.77.0
• Root cause: release YAML only declared web process type; Ruby declares
  both web and task with the same command
• Fix: add task to default_process_types in writeReleaseYaml()
• Escape single quotes in command (' → '' in YAML single-quoted scalar)
• Add docs: CF task usage in container-spring_boot.md (with cross-reference)
  and container-java_main.md (PropertiesLauncher pattern, --env CF CLI v7+)

Test plan

• go test ./src/java/... passes
• YAML single-quote escaping verified by unit test (yaml.Unmarshal round-trip)
• cf run-task without --command works on app staged with Go buildpack
• cf run-task --env JAVA_OPTS="-Dloader.main=..." works with PropertiesLauncher

The two unchecked items require manual CF verification. The Switchblade
integration test framework has no task API, so these cannot be automated
in the current test suite. The unit test for writeReleaseYaml verifies
the YAML output is correct; runtime behavior needs a live CF environment.

Fixes: #1323

[Copilot]

Pull request overview

This pull request updates the finalize phase to emit a task process type in the Cloud Foundry release YAML (alongside web) so cf run-task works without requiring an explicit --command, aligning behavior with other buildpacks.

Changes:

• Emit both web and task under default_process_types with identical commands in writeReleaseYaml().
• Add tests asserting both process types are present and (intended to be) command-identical.
• Add documentation describing CF task usage and the PropertiesLauncher/-Dloader.main pattern.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/java/finalize/finalize.go	Adds task to default_process_types in generated release YAML.
src/java/finalize/finalize_test.go	Adds/updates tests to validate task emission and command equivalence.
docs/container-spring_boot.md	Documents CF task behavior and runtime main-class override guidance for Spring Boot apps.
docs/container-java_main.md	Documents CF task behavior and PropertiesLauncher/-Dloader.main override guidance for Java Main container.

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 4 comments.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated no new comments.