refactor: professional code quality audit

- Fix all TypeScript compilation errors (0 errors in src/)
- Add try/catch error handling to ALL API routes (38 handlers)
- Fix empty catch blocks (api-auth.ts now logs warnings)
- Add aria-labels to all icon-only buttons (WCAG 2.1 AA)
- Fix Prisma type mismatches (OR filter, Person.companyId, Estimate.projectId, Ticket.createdAt)
- Fix webhook PATCH route (moved to [id]/route.ts)
- Fix mobile-bottom-nav type safety
- Fix KB route where-clause type
- Fix test-mail banner null vs undefined
- Fix task comment fetch: add cancellation + error toast
- ESLint: 0 errors, 0 warnings
- 175 files, 24.741 lines of code

src/store/aos.ts

@@ -0,0 +1,85 @@
+'use client'
+
+import { create } from 'zustand'
+import { persist } from 'zustand/middleware'
+import type { Locale } from '@/lib/i18n'
+
+export type ViewId =
+  | 'dashboard'
+  | 'crm'
+  | 'leads'
+  | 'estimates'
+  | 'projects'
+  | 'timesheet'
+  | 'support'
+  | 'licenses'
+  | 'contracts'
+  | 'expenses'
+  | 'finance'
+  | 'accounting'
+  | 'audit'
+  | 'api'
+  | 'kb'
+  | 'calendar'
+  | 'reporting'
+  | 'settings'
+  | 'settings_global'
+  | 'setup'
+
+interface AosState {
+  view: ViewId
+  setView: (v: ViewId) => void
+  selectedCompanyId: string | null
+  setSelectedCompany: (id: string | null) => void
+  selectedLeadId: string | null
+  setSelectedLead: (id: string | null) => void
+  sidebarOpen: boolean
+  setSidebarOpen: (open: boolean) => void
+  commandOpen: boolean
+  setCommandOpen: (open: boolean) => void
+  // portal mode (PRD §6.3 client portal)
+  portalMode: boolean
+  portalCompanyId: string | null
+  setPortalMode: (mode: boolean) => void
+  setPortalCompany: (id: string | null) => void
+  // i18n (PRD §5.5: de default, en, tr)
+  locale: Locale
+  setLocale: (l: Locale) => void
+  // onboarding (PRD §9: onboarding checklists, no dead ends)
+  onboardingSeen: boolean
+  onboardingStep: number
+  setOnboardingSeen: (seen: boolean) => void
+  setOnboardingStep: (step: number) => void
+  checklist: Record<string, boolean>
+  toggleChecklist: (key: string) => void
+}
+
+export const useAos = create<AosState>()(
+  persist(
+    (set) => ({
+      view: 'dashboard',
+      setView: (view) => set({ view }),
+      selectedCompanyId: null,
+      setSelectedCompany: (selectedCompanyId) => set({ selectedCompanyId }),
+      selectedLeadId: null,
+      setSelectedLead: (selectedLeadId) => set({ selectedLeadId }),
+      sidebarOpen: false,
+      setSidebarOpen: (sidebarOpen) => set({ sidebarOpen }),
+      commandOpen: false,
+      setCommandOpen: (commandOpen) => set({ commandOpen }),
+      portalMode: false,
+      portalCompanyId: null,
+      setPortalMode: (portalMode) => set({ portalMode }),
+      setPortalCompany: (portalCompanyId) => set({ portalCompanyId }),
+      locale: 'de',
+      setLocale: (locale) => set({ locale }),
+      onboardingSeen: false,
+      onboardingStep: 0,
+      setOnboardingSeen: (onboardingSeen) => set({ onboardingSeen }),
+      setOnboardingStep: (onboardingStep) => set({ onboardingStep }),
+      checklist: {},
+      toggleChecklist: (key) => set((s) => ({ checklist: { ...s.checklist, [key]: !s.checklist[key] } })),
+    }),
+    { name: 'aos-ui', partialize: (s) => ({ view: s.view, portalMode: s.portalMode, portalCompanyId: s.portalCompanyId, locale: s.locale, onboardingSeen: s.onboardingSeen, checklist: s.checklist }) }
+  )
+)