docs: sync ship step references after renumber

CLAUDE.md: "At /ship time (Step 5)" → "(Step 13)" — CHANGELOG is now
  explicitly Step 13 after the renumber (was implicit between old
  Step 4 and Step 5.5).
TODOS.md: "Step 3.4 coverage audit" → "Step 7" — references the open
  TODO for auto-upgrading ★-rated tests, which hooks into the coverage
  audit step.

Both are historical references to ship's step numbering that became
stale when clean integer renumbering landed in 566d42c2.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -275,7 +275,7 @@ own version bump and CHANGELOG entry. The entry describes what THIS branch adds
 not what was already on main.
 
 **When to write the CHANGELOG entry:**
-- At `/ship` time (Step 5), not during development or mid-branch.
+- At `/ship` time (Step 13), not during development or mid-branch.
 - The entry covers ALL commits on this branch vs the base branch.
 - Never fold new work into an existing CHANGELOG entry from a prior version that
   already landed on main. If main has v0.10.0.0 and your branch adds features,

TODOS.md

@@ -382,7 +382,7 @@ Linux cookie import shipped in v0.11.11.0 (Wave 3). Supports Chrome, Chromium, B
 
 ### Auto-upgrade weak tests (★) to strong tests (★★★)
 
-**What:** When Step 3.4 coverage audit identifies existing ★-rated tests (smoke/trivial assertions), generate improved versions testing edge cases and error paths.
+**What:** When Step 7 coverage audit identifies existing ★-rated tests (smoke/trivial assertions), generate improved versions testing edge cases and error paths.
 
 **Why:** Many codebases have tests that technically exist but don't catch real bugs — `expect(component).toBeDefined()` isn't testing behavior. Upgrading these closes the gap between "has tests" and "has good tests."