refactor(backend): clean up models setup, improve ip utils, add adr docs

- Extract ADR documents for architectural decisions (SQLite, FastAPI, React, APScheduler, Scheduler)
- Refactor setup.py: improve code structure and readability
- Add IP validation utilities with test coverage
- Update frontend components (BanTable, HistoryPage)
- Add pre-commit hooks and CONTRIBUTING.md
- Add .editorconfig for consistent coding standards

CONTRIBUTING.md

@@ -0,0 +1,118 @@
+# Contributing to BanGUI
+
+Welcome! This guide covers everything you need to know to set up your dev environment, understand the codebase, and submit changes.
+
+---
+
+## Dev Setup
+
+### 1 — Clone and init
+
+```bash
+git clone <repo-url>
+cd BanGUI
+cp .env.example .env
+python -c 'import secrets; print(secrets.token_hex(32))'
+# paste output as BANGUI_SESSION_SECRET in .env
+```
+
+### 2 — Start the stack
+
+```bash
+make up
+```
+
+Backend: http://127.0.0.1:8000 · Frontend (Vite proxy): http://127.0.0.1:5173
+
+### 3 — Pre-commit hooks
+
+**Backend** (pre-commit, all languages):
+
+```bash
+pip install pre-commit
+pre-commit install
+```
+
+**Frontend** (husky, TypeScript validation):
+
+```bash
+cd frontend && npm install
+npx husky install
+```
+
+Hooks run automatically on every `git commit`. To run manually:
+
+```bash
+pre-commit run --all-files        # backend hooks
+cd frontend && npm run validate:types  # frontend type check
+```
+
+---
+
+## Project Structure
+
+```
+BanGUI/
+├── backend/          Python FastAPI app
+│   └── app/
+│       ├── routers/  HTTP endpoint handlers
+│       ├── services/ Business logic
+│       ├── repos/   Data access
+│       ├── models/   Pydantic request/response/domain models
+│       └── utils/   Shared helpers
+├── frontend/         React + TypeScript + Fluent UI v9
+│   └── src/
+│       ├── pages/   Route-level page components
+│       ├── components/  Reusable UI components
+│       ├── hooks/   Custom React hooks
+│       └── types/   Shared TypeScript types
+├── Docs/             Architecture, design, and feature documentation
+└── Docker/           Container compose files
+```
+
+---
+
+## Code Quality
+
+| Tool | Scope | Command |
+|---|---|---|
+| `ruff` | Backend linting | `cd backend && ruff check .` |
+| `ruff-format` | Backend formatting | `cd backend && ruff format .` |
+| `mypy --strict` | Backend type checking | `cd backend && mypy --strict app` |
+| `tsc --noEmit` | Frontend type checking | `cd frontend && tsc --noEmit` |
+| `eslint` | Frontend linting | `cd frontend && eslint src` |
+| `prettier --check` | Frontend formatting | `cd frontend && prettier --check src` |
+
+**All checks must pass before committing.** CI runs the same suite.
+
+---
+
+## Testing
+
+```bash
+# Backend
+cd backend && pytest --cov=app --cov-report=term-missing
+
+# Frontend — run once
+cd frontend && npm test
+```
+
+---
+
+## Stack
+
+| Layer | Stack |
+|---|---|
+| Backend | Python 3.12+, FastAPI, Pydantic v2, aiosqlite, structlog |
+| Frontend | TypeScript, React, Fluent UI v9, Vite |
+| Container | Docker Compose (development + production) |
+
+---
+
+## Key Docs
+
+- [Instructions.md](Docs/Instructions.md) — Agent operating rules
+- [Backend-Development.md](Docs/Backend-Development.md) — Backend conventions
+- [Web-Development.md](Docs/Web-Development.md) — Frontend conventions
+- [Features.md](Docs/Features.md) — Complete feature list
+- [Architekture.md](Docs/Architekture.md) — System architecture