Close remaining coverage gap to 90% QASP target (branches lag furthest)

[fpigeonjr]

Parent

#576

Context

#637 re-measured coverage after all ten epic sub-issues (#627–#636) landed and locked coverage-floor.json at the measured values. None of the four metrics reached the 90% QASP target:

metric	measured	target	gap
statements	88.73%	90%	1.27 pts
branches	78.65%	90%	11.35 pts
functions	85.90%	90%	4.10 pts
lines	88.72%	90%	1.28 pts

Branches lags furthest by a wide margin and should be the priority for follow-up spec work.

What to build

Add specs (or extend existing ones) that exercise the untested branches in the modules below, re-run npm --prefix test-app test, and bump coverage-floor.json via npm run coverage:bump as its own standalone commit once all four metrics are at or above 90%.

Thinnest branch coverage (from the #637 measurement)

• src/ui-kit/experimental/patterns/layout/components/** — several files at 0% branch coverage: main.component.ts, core/overlay/overlay.ts, core/overlay/overlay-container.ts, core/overlay/scroll/scrollable.ts, core/overlay/position/viewport-ruler.ts, core/coordination/unique-selection-dispatcher.ts, expansion/expansion-panel.ts, expansion/expansion-panel-header.ts, expansion/accordion-item.ts, actionbar.component.ts, page/page.component.ts
• src/ui-kit/components/banner/banner.component.ts — 0%
• src/ui-kit/components/header-next/header.component.ts — 0%
• src/ui-kit/experimental/tabs/tab-nav-bar/tab-nav-bar.ts — 0%
• src/ui-kit/layout/pagination/pagination.component.ts — 10%
• src/ui-kit/pipes/short-date/short-date.pipe.ts — 33%
• src/ui-kit/experimental/patterns/layout/architecture/update/reducer.ts — 33%
• src/ui-kit/form-templates/international-phone/international.component.ts — 33%
• src/ui-kit/experimental/listbox/listbox.component.ts — 36%
• src/ui-kit/components/sidenav/services/sidenav.service.ts — 38%
• src/ui-kit/components/data-table/sort-header.component.ts — 42%
• src/ui-kit/experimental/icon/fa-icon/shared/utils/normalize-icon-spec.util.ts — 42%
• src/ui-kit/components/multiselect-dropdown/multiselect-dropdown.component.ts — 48%
• src/ui-kit/experimental/hierarchical/autocomplete/autocomplete.component.ts — 49% (82 branches — largest single opportunity)

Acceptance criteria

• Statements, branches, functions, and lines all measured at or above 90% in test-app/coverage/coverage-summary.json
• coverage-floor.json bumped via coverage:bump and committed as its own standalone commit/PR
• CI passes with the raised floor
• Parent epic (EPIC: Raise sam-ui-elements test coverage #576) re-reviewed and closed if this closes out its remaining AC

Blocked by

• Lock coverage-floor gate at 90% QASP target (epic top-off) #637