feat(skills): agent-skills catalog tranche 4+ — 16 skills vs Telnyx's 244; grow toward per-domain coverage

Telnyx-parity review (2026-07-06). Both sites pass the agent-discovery-file check, but the catalogs differ by an order of magnitude: Telnyx publishes 244 skills at /.well-known/agent-skills/index.json; we publish 16 (tranches 1–3, #4876/#4877). Each skill is an installable entry point (npx skills add koala73/worldmonitor) and a named, crawlable artifact.

We have 39 MCP tools and 193 REST operations backing only 16 skills. Candidate expansion axes:
- Per-domain monitors not yet covered (energy intelligence, supply-chain, trade flows, protests, webcams/streams)
- Composite workflows (e.g. "assess market transmission of a geopolitical event" chaining conflict → chokepoint → market tools)
- Per-variant skills (tech/finance/commodity/energy monitor angles)

Keep the content-safety sections pattern from #4879/#4880/#4881 (feeds are adversary-adjacent) on every new skill.

Start with /.well-known/agent-skills/index.json and the existing tranche 1–3 skills referenced by #4876 and #4877, then review the 39 MCP tools and 193 REST operations for uncovered domains or workflows. Done means adding an agreed tranche of crawlable, installable skills toward broader coverage, with the content-safety sections from #4879, #4880, and #4881 on every new skill.

Written by the indexing model from the issue text.