test: move the full office-hours workflow to marathon; add a periodic design-draft checkpoint

The full startup workflow runs 1–3 real spec-review rounds (~280s each) and
hit its 1200s capture in run 36385945043 at finalize. Review depth is the
product's loop, so the case cannot fit a blocking lane without cutting
rounds. It is now marathon tier with every assertion unchanged.

skill-e2e-office-hours-design-draft.test.ts (periodic) runs the same fixed
interview only through the Write that creates the design (269s in that run)
and applies the full validator's design-draft checks, the required section
reads and the launch/foreign-skill-read guards. validateOfficeHoursDesignDraft
is extracted from validateOfficeHoursCompletion, which still applies it.

Selection: office-hours-design-draft is registered periodic; the marathon-only
file is already excluded from the gate and periodic plans by the B5 planner
rule. Tier-alignment regexes and the valid-tier check accept 'marathon'.
A type-only cast in plan-scope-selection.test.ts removes a diagnostic whose
union print order made the ratchet identity unstable; baseline tightened.

test/e2e-tier-alignment.test.ts

@@ -33,13 +33,13 @@ const TEST_DIR = import.meta.dir;
 // Both quote styles — a mechanical refactor to double quotes must not
 // silently drop a file from the invariant (fail-open is the defect class
 // this test exists to kill).
-const SELF_GATE_RE = /EVALS_TIER\s*===\s*['"](gate|periodic)['"]/g;
+const SELF_GATE_RE = /EVALS_TIER\s*===\s*['"](gate|periodic|marathon)['"]/g;
 // Consolidated gate helper (test/helpers/e2e-gate.ts). Both regexes stay
 // active: migrated files self-gate via `describeE2ETier('<tier>')` (or the
 // boolean form `e2eTierEnabled('<tier>')`), while stragglers still using the
 // raw predicate are caught by SELF_GATE_RE above. The tier argument maps to
 // the declared tier exactly like the raw predicate's tier literal did.
-const HELPER_GATE_RE = /\b(?:describeE2ETier|e2eTierEnabled)\(\s*['"](gate|periodic)['"]/g;
+const HELPER_GATE_RE = /\b(?:describeE2ETier|e2eTierEnabled)\(\s*['"](gate|periodic|marathon)['"]/g;
 
 /**
  * Ratchet, not amnesty (the contract KNOWN_MATRIX_GAPS pioneered before the