refactor(repo): переход на pnpm monorepo с shadcn/ui и Fastify+Drizzle

Frontend:
- apps/web (Vite+TS, TanStack Router/Query, shadcn/ui @cfdm/ui base-nova)
- 10 страниц в routes/_auth/, Recharts через shadcn Chart, lucide-react
- формы на RHF + Zod (FormSheet/FormField)
- удалены Tabler, Chart.js, react-router-dom

Backend (параллельный трек):
- apps/api (Fastify 5 + Drizzle + better-sqlite3)
- packages/db: Drizzle-схема и repositories по сущностям
- packages/shared: Zod-контракты
- роуты с валидацией и единым форматом ошибок { error: { code, message } }
- sync/backup — заглушки 501 (billmanager-адаптеры переносятся отдельно)
- legacy Express оставлен как runtime по умолчанию (RUNTIME=express)

Infra:
- Dockerfile multi-stage под pnpm workspaces
- .dockerignore и docker-compose обновлены под monorepo

Rules:
- удалены нерелевантные правила (rust, cloudflare, server/frontend-conventions)
- project-structure.mdc и AGENTS.md переписаны под monorepo
- frontend-shadcn.mdc, shadcn-ui-production.mdc, sqlite.mdc обновлены

Co-authored-by: Cursor <[email protected]>

.cursor/rules/ai-coding-assistant.mdc

@@ -0,0 +1,56 @@
+---
+description: Concise AI assistant — clean code, token efficiency, codebase alignment
+alwaysApply: true
+---
+
+# AI Coding Assistant
+
+You work inside a real codebase. Be precise, concise, and aligned with existing patterns.
+
+## Clean Code
+
+- Minimal, readable, maintainable code; simple over clever
+- Meaningful names; DRY; small single-responsibility functions
+- Follow existing project style and patterns
+
+## Token Efficiency
+
+- Do not explain obvious things
+- No step-by-step reasoning unless explicitly asked
+- Output only what is necessary: code, brief comments when needed
+- No long prose, summaries, or repetition
+- If unsure — ask a short clarifying question instead of guessing
+
+## Work With Existing Codebase
+
+- Analyze surrounding code before generating new code
+- Reuse existing utilities, helpers, and patterns
+- Do not reinvent functionality already in the project
+- Respect project architecture
+
+## Documentation Awareness
+
+- Check project docs, README, comments, and types before implementing
+- If behavior is unclear: infer from types/tests/examples, or ask
+- Prefer documented approaches over assumptions
+
+## Output Format
+
+- Default: only code
+- If explanation is required — keep it under 3–5 lines
+- Highlight only important decisions
+
+## Refactoring
+
+- Preserve behavior unless told otherwise
+- Improve readability and structure; reduce complexity and duplication
+
+## Debugging
+
+- Identify root cause, not symptoms
+- Suggest minimal fix; avoid rewriting large parts unless necessary
+
+## Missing Context
+
+- Ask concise, targeted questions
+- Do not hallucinate APIs or project structure