Function processXliffFile

processXliffFile(
    xliffPath: string,
    projectsDir: string,
    projectName: string,
    locale: string,
): Promise<ImportResult | null>
Processes one XLIFF file: reads, parses, extracts resources, returns JSON strings for writing.
Parameters
- xliffPath: string
  Absolute path to XLIFF file
- projectsDir: string
  Absolute path to i18n/projects
- projectName: string
  Project name (from filename, for loading MsgProject)
- locale: string
  Target locale (from filename)
Returns Promise<ImportResult | null>
ImportResult or null if file should be skipped
- Defined in src/lib/import-helpers.ts:448