v0.42.0

Documentation: a generated Word + PDF manual, built and attached automatically.

scripts/build-docs-docx.py assembles README + SECURITY + DOCS.md into one
printable manual — an editable .docx (via pandoc) and a reader-friendly
.pdf (via LibreOffice, no LaTeX) — and a new docs CI workflow builds both on
every push/PR (uploaded as an artifact, so a DOCS.md that stops converting fails
the check) and attaches them to each published GitHub Release. Same process the
ecoflow-panel and zwave repos use.

The reference itself was refreshed for the current release: the real
prefix-free direct-dial GXW dial plan and the SSH CLI config path (with
the P85 = 3 s rotary-safe send delay), the full-screen operator console with
its trunk-registration / STT-health / per-room-RTT signals, and a new
"Reproducing on new hardware" chapter (rebuild from a release tag; restore
config from a Home Assistant backup).