A session-close sweep for content that would have been lost. Four items.

(1) THREE PLATFORM BEHAVIOURS were recorded ONLY in CURRENT-STATE, which is a
status document that gets consolidated over time -- a durable trap does not
belong there alone. Graduated to references/platform-traps.md: MAAS auto-reserves
::1-::ffff:ffff on EVERY IPv6 subnet (so an explicit v6 band write is both
impossible and unnecessary, and is invisible in `ipranges read` -- only
`subnet reserved-ip-ranges` shows it); MAAS mode=static means EXPLICITLY
CONFIGURED, so creating a subnet addresses nothing and the carve is still owed;
and NetBox's live API returns scope.name as the DISPLAY name while this repo's
dumps normalise it to the slug, so a dump-written tool matches zero objects live.

(2) TWO OPEN QUESTIONS existed only in the session changelog -- which is
session-scoped scratch, explicitly not citable as status and consolidated away at
stage close. Both would have been lost: which host is authoritative for the gates
(now sharper, since executing R15(3) made preflight-on-voffice1 permanently
unpassable against P0-2's host-blind P5), and the provider-bundle-check arity gap
(now imminent rather than theoretical -- the apex holds the dual-family set the
renderer will emit, so the gate cannot validate what is about to be produced).
Also recorded: voffice1 tracks the precondition branch and must return to main at
merge.

(3) A latent import defect in netbox/dc-plane-apex-import.py: urllib.parse was
imported inside the __main__ guard while main() uses it. It worked only because
another module had already bound the submodule -- fragile, and it would NameError
if the file were ever imported. Moved to module scope.

Gauntlet ALL GREEN (84), repo-lint 0 fail.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HvCyrwvYTTcDYnRErfMsNf