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

frontend/src/components/BanTable.tsx

@@ -241,6 +241,7 @@ export const BanTable = memo(function BanTable({ timeRange, origin, source }: Ba
           items={banItems}
           columns={banColumns}
           getRowId={(item: DashboardBanItem) => `${item.ip}:${item.jail}:${item.banned_at}`}
+          aria-label="Ban records table"
         >
           <DataGridHeader>
             <DataGridRow>