In /embed, check document sensitivity label before processing file

[jare5d]

Added document sensitivity checker as described in issue #136. This update introduces a document sensitivity checker that processes files based on their sensitivity labels and types. The checker supports the following file formats: .docx, .pptx, .xlsx, and .pdf.

• DOC_FLTR_ENABLED: Enables or disables sensitivity label filtering.

  • Type: boolean
  • Accepted values: true, 1, yes (case-insensitive)
  • Default: false if not set

• DOC_FLTR_ALLOWED_LABELS: A JSON array of allowed sensitivity labels. If a document's label is not included in this list, it will be rejected when filtering is enabled.

  • Type: JSON list of strings
  • Format: Must be a valid JSON array (e.g., ["public", "confidential"])
  • Note: Labels are normalized (trimmed and lowercased). Special characters and spaces are allowed.
  • Default: If unset or an empty array, all labels are allowed
  • Example: DOC_FLTR_ALLOWED_LABELS=["public", "personal", "confidential", "company name - confidential"]

• DOC_FLTR_FILE_TYPES: A JSON array of allowed file extensions (e.g., "pdf", "docx"). Only these types will be checked for labels.

  • Type: JSON list of strings
  • Note: File extensions should be lowercase and without dots.
  • Default: If unset, defaults to ["pdf", "docx", "xlsx", "pptx"]
  • Example: DOC_FLTR_FILE_TYPES=["pdf", "docx"]

This ensures that files are checked according to the specified document types and sensitivity labels, providing flexibility for different configurations.