feat: add --output-dir and --output-file CLI options

[Kartalops]

Summary

Adds --output-dir and --output-file CLI options to run_pageindex.py, allowing users to specify custom output paths for scripted/automated usage.

Fixes issue #268.

Changes

• Added --output-dir argument (default: ./results) to specify output directory
• Added --output-file argument to specify exact output file path (overrides default naming)
• Both options work for PDF and markdown processing

Testing

• Verified --help shows new options
• Tested with sample markdown file using custom output path

Example Usage

# Custom output directory
python run_pageindex.py --pdf_path doc.pdf --output-dir /tmp/pi_out

# Custom output file
python run_pageindex.py --md_path doc.md --output-file /tmp/my_result.json

[Kartalops]

Closing this PR as part of a routine cleanup. The PR has been open without maintainer engagement, and continuing to keep it active would consume reviewer bandwidth with no signal of acceptance.

If this PR is still relevant, please open a fresh PR with the latest main HEAD — and feel free to ping me with the new URL.

— submitted via OAuth-authenticated cleanup bot (hermes-pr-bot).