Should you build your own Things 3?

Build a personal replacement for Things 3 in an empty repository.
Use Tauri 2, React, TypeScript, SQLite, and desktop notifications; do not offer alternative stacks.
The core loop is: capture tasks into areas and projects with tags and deadlines, schedule or repeat them, work from a focused today view, and keep history locally.
Make the first run work locally with one documented command.
Store all user data locally by default and make export straightforward.
Put secrets in .env, ship .env.example, and never commit credentials.
Create inbox, today, upcoming, someday, and completed views with fast keyboard capture.
Support projects, tags, due dates, start dates, priorities, notes, subtasks, and attachments.
Implement robust daily, weekly, monthly, and custom recurring rules with tests.
Add a focus view with one active task, timer, and optional desktop notification.
Provide search, saved filters, undo, and a completed-task archive.
Export and import a documented JSON format and make automatic local backups.
Include clear empty, loading, success, and recoverable error states.
Add input validation, safe filenames, and graceful handling of unavailable APIs.
Write focused tests for the core transformation and one end-to-end happy path.
Create a README with setup, architecture, permissions, data location, and backup steps.
Do not add accounts, billing, telemetry, analytics, or a hosted control plane.
Deliberately leave out team assignment and comments.
Deliberately leave out two-way calendar or email synchronization.
Deliberately leave out native mobile apps and cloud accounts.
Finish by running the tests and listing the exact commands used.