v1.11.0 — OOXML format conversion (ODF ↔ DOCX/XLSX/PPTX)

Bidirectional bridges between ODT/ODS/ODP and their Microsoft Office
counterparts (DOCX/XLSX/PPTX), plus the legacy MS Office binary formats
(DOC/XLS/PPT), via headless LibreOffice. Closes the last interop gap with
the OOXML world.

Added

• convert_with_soffice(input, target_format, outdir, filter_name=None)
  in odf_lib.odf_common, in the public API. Isolated -env:UserInstallation
  temp profile — the real LibreOffice user profile is never touched.
  render_to_pdf is now a one-line wrapper around it.
• skills/odt/scripts/convert.py — ODT ↔ DOCX/DOC.
• skills/ods/scripts/convert.py — ODS ↔ XLSX/XLS.
• skills/odp/scripts/convert.py — ODP ↔ PPTX/PPT.
• Cross-family conversions (e.g. ODT → XLSX) are rejected with a clear hint.

Changed

• The previous "DOCX/PPTX/XLSX import-and-edit" README non-goal is precisely
  scoped to in-place native-OOXML editing only. One-shot conversion
  in either direction ships here. For sustained DOCX work the natural
  pattern is convert.py → edit as ODF → convert.py back.

See CHANGELOG.md for the full release notes.