revert: Remove Java cookbook from main (was merged to wrong branch)

[brunoborges]

Summary

PRs #1313 and #1314 were accidentally merged into main instead of staged. This reverts both merge commits to remove the Java cookbook from main.

The content has been re-targeted to staged in a separate PR.

Reverts

• Revert of fix: Java cookbook recipes to compile with copilot-sdk-java 0.2.1-java.1 #1314 (fix: Java cookbook recipes to compile with copilot-sdk-java 0.2.1-java.1)
• Revert of Add Java SDK cookbook with 7 recipes #1313 (Add Java SDK cookbook with 7 recipes)

[github-actions]

⚠️ This PR targets main, but PRs should target staged.

The main branch is auto-published from staged and should not receive direct PRs.
Please close this PR and re-open it against the staged branch.

You can change the base branch using the Edit button at the top of this PR,
or run: gh pr edit 1315 --base staged

[Copilot]

Pull request overview

Reverts previously merged Java Copilot SDK cookbook content from main (it was intended for staged) and updates cookbook indexes to reflect the removal.

Changes:

• Remove the Java section and execution instructions from the Copilot SDK cookbook index.
• Update the top-level cookbook README to remove Java from the language list.
• Delete all Java cookbook recipe docs and runnable JBang examples from main.

Show a summary per file

File	Description
cookbook/README.md	Removes Java from the Copilot SDK Cookbook language list (and fixes the list formatting).
cookbook/copilot-sdk/README.md	Removes the Java recipe section + Java “Running Examples” instructions; updates supported language count.
cookbook/copilot-sdk/java/README.md	Deletes the Java cookbook landing page from main.
cookbook/copilot-sdk/java/accessibility-report.md	Deletes the Java accessibility report recipe doc from main.
cookbook/copilot-sdk/java/error-handling.md	Deletes the Java error-handling recipe doc from main.
cookbook/copilot-sdk/java/managing-local-files.md	Deletes the Java local-files recipe doc from main.
cookbook/copilot-sdk/java/multiple-sessions.md	Deletes the Java multiple-sessions recipe doc from main.
cookbook/copilot-sdk/java/persisting-sessions.md	Deletes the Java persisting-sessions recipe doc from main.
cookbook/copilot-sdk/java/pr-visualization.md	Deletes the Java PR-visualization recipe doc from main.
cookbook/copilot-sdk/java/ralph-loop.md	Deletes the Java Ralph loop recipe doc from main.
cookbook/copilot-sdk/java/recipe/README.md	Deletes the Java runnable-recipes README from main.
cookbook/copilot-sdk/java/recipe/AccessibilityReport.java	Deletes the Java runnable AccessibilityReport JBang script from main.
cookbook/copilot-sdk/java/recipe/ErrorHandling.java	Deletes the Java runnable ErrorHandling JBang script from main.
cookbook/copilot-sdk/java/recipe/ManagingLocalFiles.java	Deletes the Java runnable ManagingLocalFiles JBang script from main.
cookbook/copilot-sdk/java/recipe/MultipleSessions.java	Deletes the Java runnable MultipleSessions JBang script from main.
cookbook/copilot-sdk/java/recipe/PersistingSessions.java	Deletes the Java runnable PersistingSessions JBang script from main.
cookbook/copilot-sdk/java/recipe/PRVisualization.java	Deletes the Java runnable PRVisualization JBang script from main.
cookbook/copilot-sdk/java/recipe/RalphLoop.java	Deletes the Java runnable RalphLoop JBang script from main.

Copilot's findings

• Files reviewed: 18/18 changed files
• Comments generated: 0