[yeshion23333]

Description

Importing a single Markdown file with --args parse_mode:no_split --processing-mode vectors_only can fail with PROCESSING_ERROR: not a directory. Privacy sanitization uses the temporary artifact container's type to choose directory traversal, even when the resolved document root inside that container is a file. Local output stores can silently skip that file instead.

Pass the resolved root_is_file into the sanitizer so it reads and sanitizes the document directly before persistence and indexing. Keep the existing directory traversal and file-type artifact fallback.

Human Involvement

• A human participated in the implementation or review loop
• This PR was generated entirely by AI agents without human participation in the loop

Related Issue

Follow-up to #6161.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactoring (no functional changes)
• Performance improvement
• Test update

Changes Made

• Forward the existing document-root classification into Privacy sanitization.
• Sanitize file roots directly while retaining the directory traversal path.

Testing

• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have tested this on the following platforms:
  • Linux
  • macOS
  • Windows

No new regression tests were added. Validation:

• 47 existing tests passed across Markdown no-split parsing, resource routing, processing modes, local artifact persistence, and Privacy sanitization.
• One-off reproduction using the actual Markdown parser and Privacy sanitizer with AGFS/local output-store adapters: confirmed the original file-root failure/skip, successful sanitization and matching manifest hashes after the fix, and unchanged directory traversal/internal-sidecar handling.
• ruff check, ruff format --check, and git diff --check passed.

Checklist

• My code follows the project's coding style
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published