[KYUUBI #7351] Ignore GitHub Copilot and Claude folders by Git

### Why are the changes needed?

As title.

### How was this patch tested?

Review.

### Was this patch authored or co-authored using generative AI tooling?

No, but this is for AI.

Closes #7351 from pan3793/ignore-ai-dir.

Closes #7351

83da218 [Cheng Pan] Ignore GitHub Copilot and Claude folders by Git

Authored-by: Cheng Pan <chengpan@apache.org>
Signed-off-by: Cheng Pan <chengpan@apache.org>

Author: pan3793

.gitignore

@@ -30,6 +30,7 @@
 .metals/
 .cache
 .classpath
+.claude/
 .ensime
 .ensime_cache/
 .ensime_lucene
@@ -89,3 +90,10 @@ kyuubi-server/src/main/antlr4/org/apache/kyuubi/sql/gen/
 # For draw.io
 .$*.bkp
 .$*.dtmp
+
+# For GitHub Copilot
+.github/copilot-instructions.md
+.github/agents/
+.github/instructions/
+.github/prompts/
+.github/skills/