fix(graph): increase entity extraction output budget

[JYao-Chen]

Description

Entity/relationship extraction can produce JSON responses containing many nodes and relations. The previous 4096-token output budget can truncate otherwise valid graph payloads before the closing JSON structure, causing parsing failures during both document graph extraction and query entity extraction because both paths use NewExtractor.

This change raises that shared output budget to 8192 tokens and adds a regression test for the configured extractor options.

Type of Change

• 🐛 Bug fix
• 🧪 Test

Related Issue

N/A

Testing

• go test ./internal/application/service/chat_pipeline -count=1
• go vet ./internal/application/service/chat_pipeline
• git diff --check origin/main...HEAD

Checklist

• git diff --check origin/main...HEAD passes
• Changed source files are formatted
• Targeted tests for the changed packages/components pass
• Diff-scoped lint passes where applicable
• Full-repository checks were run, or any unrelated/environment-dependent failures are documented above
• Self-reviewed the code
• Added/updated tests covering the change
• Updated related documentation
• Breaking changes are clearly called out in the description above

Screenshots / Recordings

N/A