feat: add frontend infrastructure libraries (ky, Zustand, MUI, dayjs, clsx, tanstack-table, rhf, zod)
- install ky, zustand, @mui/material, @fontsource/roboto, dayjs, clsx
- install @tanstack/react-table, react-hook-form, zod, @hookform/resolvers
- create kyClient.ts with auth interceptors
- create Zustand store for session (useSessionStore.ts)
- add MUI theming (theme.ts, ThemeProvider in AppProviders)
- add dayjs utils with ru locale (formatDate, formatRelative)
- add clsx cn() utility
- add base Table component using @tanstack/react-table
- create ADR-015 documenting architectural decisions
- create SDD artifacts: spec.md, plan.md, tasks.md
- build, lint, and 111 tests passing