docs: add Mycelium to community plugins

[arjunrajlab]

Summary

• Add Mycelium to the Development & Workflow community plugins section.
• Describe its durable analytical-project memory, provenance, conventions, and workflow support for Claude Code and Codex.

This submission follows the invitation in arjunrajlaboratory/mycelium#82.

Verification

• Confirmed the Claude Code and Codex plugin manifests parse successfully.
• Initialized a fresh Mycelium repository and passed its structural validator.
• Confirmed the latest Mycelium main validation workflow completed successfully: https://github.com/arjunrajlaboratory/mycelium/actions/runs/33156469988
• Kept the catalog change to one README entry in alphabetical order.

[github-actions]

✅ Contribution check passed. @arjunrajlab, catalog validation succeeded.

scan passed

All 1 source-repository scanner job(s) passed. Catalog validation passed.

Recommended: add scanner CI for security

This listing can merge without it. HOL still scans arjunrajlaboratory/mycelium independently.

We recommend including hashgraph-online/ai-plugin-scanner-action under .github/workflows/ on push and pull_request. Continuous scanning keeps this catalog safer for MCP servers, skills, plugins, and other agent extensions people install from HOL.

Adding it:

• protects the ecosystem by catching secrets, dangerous hooks, and supply-chain issues before they ship;
• keeps the listing at the full trust score (without maintainer CI it stays eligible, with a 10% trust-score reduction);
• can surface findings in GitHub code scanning.

See CONTRIBUTING.md and SCANNER_GUIDE.md.

View the latest sweep.

[github-actions]

@arjunrajlab, this contribution is merged into HOL's catalog.

Claim your plugin

Verify ownership

• Verify ownership of arjunrajlaboratory/mycelium

Open the link for your plugin and choose "Continue with GitHub". Use the GitHub account that maintains the repository. HOL requests only read:user and user:email; it does not request repository write access.

After verification, the listing gets an owner-verified badge and the plugin dashboard shows its trust score, installs, and engagement. If GitHub permissions are inconclusive, the claim may require review.

[kantorcodes]

Hi @arjunrajlab — a quick follow-up about your plugin arjunrajlaboratory/mycelium.

The listing is live in the HOL Registry, and ownership verification is still available at HOL Guard.

Verify ownership with the GitHub account that owns the repository to unlock the owner-verified badge, plugin analytics, and the author dashboard. No repository write access is needed.

We may follow up again later if ownership verification is still incomplete.

If you already completed verification, no action is needed — the next scheduler run will stop these reminders.