Add Tura as an open-source coding agent

[Yohjisakamoto]

Following CONTRIBUTING_TO_OSB.md, I would like to submit a standalone open-source development tool.

Add open source tool: Tura

• Repository: https://github.com/Tura-AI/tura
• Website: https://turaai.net/
• Description: A local, open-source coding agent with CLI, TUI, desktop, and optional web interfaces. It uses structured macro command execution to reduce repeated model round trips and supports configurable agents and task-scoped runtime state.
• Category: Development Tools
• Features: Local/self-hosted operation, CLI and TUI workflows, desktop and optional web UI, multi-session work, custom agents, task checkpoints and context compaction, Ollama and custom OpenAI-compatible providers

Additional information

• License: AGPL-3.0-or-later
• Primary language: Rust
• Documentation: https://github.com/Tura-AI/tura#readme
• Published benchmark methodology and evidence: https://turaai.net/benchmark
• Related technical article: https://turaai.net/blog#token-saving-plugins-are-mostly-stupid-idea

Disclosure: I am submitting this on behalf of the Tura project.