These import paths relied on the private EE module that was deleted from
the repo. In the community build they either threw 'enterprise license'
(DOCX/PDF) or silently no-op'd (Confluence). The frontend buttons were
already removed in 38064064; this cleans up the dead backend stubs.
- import.service.ts: drop processDocx/processPdf methods, their dispatcher
branches, the pageId computation + insertPage spread, and the now-unused
moduleRef param/ModuleRef import
- file-import-task.service.ts: drop the Confluence branch and the now-unused
moduleRef param/ModuleRef import
- import.controller.ts: restrict file extensions to .md/.html and zip
sources to generic/notion; update the error message accordingly
- file.utils.ts: remove Confluence from the FileImportSource enum
- features.ts: remove the unused CONFLUENCE_IMPORT/DOCX_IMPORT/PDF_IMPORT
feature keys
The isConfluenceImport logic in import-attachment.service.ts is intentionally
left in place (real shared attachment-parsing code, not a stub); its removal
is a separate, riskier refactor.
