Fixes#1445
This PR resolves the issue where SingleFile was not respecting Chrome
user data directory and other Chrome launch options that work for other
Chrome-based extractors (PDF, Screenshot, etc.).
## Changes
- Added `SINGLEFILE_CHROME_ARGS` config option with fallback to
`CHROME_ARGS`
- Updated SingleFile extractor to pass Chrome arguments via
`--browser-args`
- Updated documentation
This ensures SingleFile respects the same Chrome configuration as other
Chrome-based extractors.
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