Docs: CI1, decision E-CI1, the landing wording

decisions.md gains E-CI1, the owner's decision of 2026-10-09 adopting
the CI time audit: (a) reviews start at the push, (b) a landing whose
tree is the candidate's, on a candidate with a green exact-SHA run,
fast-forwards the phase branch at once and records its own runs
afterwards, waiting for them otherwise, (c) the CI speedups, no check
removed. The lane branches are the implementer's choice under (c),
owner to confirm. E-CI1 is a placeholder number, renumbered to the next
free row when CI1 lands; E25's "exact-SHA CI on the landing commit
stays required" points at it.

design.md: the landing paragraph of "One gate run per work package"
says when the phase branch moves and that land.py makes the landing;
the process rules say reviews start at the push and name prepush.sh;
the CI section records CI1 as built.

tracker.md: a "Process packages" section with CI1's row, an
owner-requested package outside the T-sequence.

Signed-off-by: Adi Wadaskar <awadaskar@nvidia.com>

Author: adi-kumo