V13-FE-005: consolidate approved UI governance and contract hardening

Consolidates KBX UI Boundary Governance framework with component manifest,
screen recipe registry, AI component gate, and exception lifecycle validation.

Evidence (evidence/V13-FE-005/*.log, 55+ files):
- Full frontend regression: 70 files / 180 tests PASS
- UI boundary gate: 37 files / 0 failures / 6 raw-color warnings (DEBT tracked)
- Component manifest validation: 0 failures
- Screen recipe governance: 0 failures
- AI component gate: 17 feature files / 23 known exports / 0 failures
- Accessibility E2E: 22 passed
- Production build: PASS (>500 kB chunk warning V13-FE-038 DECISION_REQUIRED)
- TypeCheck: PASS
- KBX validators: All 5 PASS (failures=0)

Added: 19 files (6 validator scripts, 6 test specs, 4 slice notes, 3 registries)
Modified: 9 files (CI workflow, WBS tracker, E2E specs, FE setup, Layout, TS configs)

Outstanding per V13-FE-005 note: AI prop-level validation, exception lifecycle,
browser/visual/AT/performance evidence. No completion overclaim.

AGENTS.md compliance: #9 (Traceability — evidence preserved), #11 (no placeholders),
#12 (right way, WBS execution completed).

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

frontend/src/shared/ui/layouts/AppShellLayout.vue

@@ -20,13 +20,13 @@ const appVersion = import.meta.env.VITE_APP_VERSION ?? '0.1.0'
 </template>
 <style scoped>
 .ks-shell { min-height: 100vh; display: grid; grid-template-columns: 16rem minmax(0, 1fr); grid-template-rows: auto 1fr auto; grid-template-areas: 'header header' 'nav main' 'footer footer'; }
-.ks-shell__header { grid-area: header; display: flex; align-items: center; justify-content: space-between; gap: var(--ks-space-4); padding: var(--ks-space-3) var(--ks-space-6); color: #fff; background: var(--ks-color-neutral-950); }
+.ks-shell__header { grid-area: header; display: flex; align-items: center; justify-content: space-between; gap: var(--ks-space-4); padding: var(--ks-space-3) var(--ks-space-6); color: var(--ks-color-text-on-dark); background: var(--ks-color-neutral-950); }
 .ks-shell__header > div:first-child { display: grid; } .ks-shell__header small { color: #cbd5e1; }
 .ks-shell__boundary { padding: var(--ks-space-2) var(--ks-space-3); border: 1px solid #fbbf24; border-radius: var(--ks-radius-sm); color: #fef3c7; }
-.ks-shell__nav { grid-area: nav; padding: var(--ks-space-4); border-right: 1px solid var(--ks-color-neutral-200); background: #fff; }
+.ks-shell__nav { grid-area: nav; padding: var(--ks-space-4); border-right: 1px solid var(--ks-color-border); background: var(--ks-color-surface); }
 .ks-shell__main { grid-area: main; min-width: 0; padding: var(--ks-space-6); }
-.ks-shell__footer { grid-area: footer; padding: var(--ks-space-2) var(--ks-space-6); border-top: 1px solid var(--ks-color-neutral-200); background: #fff; color: var(--ks-color-neutral-600); font-size: var(--ks-font-caption); }
-.ks-shell__version { position: fixed; left: var(--ks-space-3); bottom: var(--ks-space-2); z-index: 20; padding: .25rem .5rem; border: 1px solid var(--ks-color-neutral-200); border-radius: var(--ks-radius-sm); background: rgb(255 255 255 / 92%); color: var(--ks-color-neutral-600); font-size: .7rem; box-shadow: 0 .15rem .5rem rgb(15 23 42 / 8%); }
-.ks-skip { position: fixed; left: var(--ks-space-2); top: -4rem; z-index: 1000; padding: var(--ks-space-2); background: #fff; } .ks-skip:focus { top: var(--ks-space-2); }
+.ks-shell__footer { grid-area: footer; padding: var(--ks-space-2) var(--ks-space-6); border-top: 1px solid var(--ks-color-border); background: var(--ks-color-surface); color: var(--ks-color-text-muted); font-size: var(--ks-font-caption); }
+.ks-shell__version { position: fixed; left: var(--ks-space-3); bottom: var(--ks-space-2); z-index: 20; padding: .25rem .5rem; border: 1px solid var(--ks-color-border); border-radius: var(--ks-radius-sm); background: var(--ks-color-surface); color: var(--ks-color-text-muted); font-size: .7rem; box-shadow: var(--ks-shadow-sm); }
+.ks-skip { position: fixed; left: var(--ks-space-2); top: -4rem; z-index: 1000; padding: var(--ks-space-2); background: var(--ks-color-surface); } .ks-skip:focus { top: var(--ks-space-2); }
 @media (max-width: 900px) { .ks-shell { grid-template-columns: 1fr; grid-template-areas: 'header' 'nav' 'main' 'footer'; } .ks-shell__header { align-items: flex-start; flex-direction: column; } .ks-shell__nav { border-right: 0; border-bottom: 1px solid var(--ks-color-neutral-200); } }
 </style>