Resolve two consistency nits from review: shape-spec said plan-review was
'optional' for Small while the README canonical table says skip it (align
to skip); and the changelog now describes both misuse directions the new
rationalizations guard against, not just gate-skipping.
Add one rationalization row to each design-phase skill against using the
tier model as an excuse to skip the evidence gate (verification-gate /
code-review-loop never scale by tier), and record the change in the
changelog.
Add a Trivial/Small/Standard tier model so the design ceremony scales to
the change while the evidence gate never does. README gains a canonical
'Sizing the work' table + the non-negotiable rule (verification-gate and
code-review-loop always run); shape-spec gets a Step 0 sizing gate;
write-plan and plan-review state which tier they belong to.
duthaho
