[admin] Submit toolbelt to developer directories and aggregators

[anurag629]

Context

Part of the SEO growth initiative (#18): Phase 3: Authority and off-page.
Directory and aggregator listings are cheap, durable backlinks and a steady discovery channel for a free open-source tool set.

What to do

• Submit to Product Hunt, AlternativeTo, and relevant awesome-* lists and dev-tool roundups.
• Keep the pitch honest: free, client-side, open source, no tracking.
• Track where we are listed.

Where

External directories. Uses the existing README copy and OG assets.

Acceptance criteria

• Submitted to the target directories
• Listing URLs recorded

Notes

Branch off develop (feat/*, docs/*, chore/*), open a PR into develop, and squash-merge. See CONTRIBUTING.md.
cc @anurag629 (needs repo admin or an external account).