Add open source tool: Octomind — open-source AI agent runtime (Rust)

Using CONTRIBUTING_TO_OSB.md, please add:

Add open source tool: Octomind
- Repository: https://github.com/Muvon/octomind
- Website: https://octomind.run
- Description: Open-source AI agent runtime written in Rust: one binary that runs specialist agents on any model (OpenRouter, OpenAI, Anthropic, Google, DeepSeek, Bedrock, Ollama). MCP-native with dynamic server registration, TOML-defined agents with deterministic guardrails, runs unattended in CI or as a daemon. Ships with a registry of 137 community-built specialist agents across 35 domains.
- Category: Development Tools
- Features: API integration, Plugin system, Multi-language support, Self-hosted option, Version control

Note: Octomind (octomind.run, by Muvon) — not to be confused with OctoMind.dev (e2e testing company).

Thanks!

Read CONTRIBUTING_TO_OSB.md first, then locate the project’s tool-listing data and the existing Development Tools entries. Add Octomind with the provided repository, website, description, category, and features, preserving the distinction from OctoMind.dev; run any validation steps named in the contribution guide.

Written by the indexing model from the issue text.