Network Flows: fix MDX deploy preview + capture MDX gotchas in skills (#22445)
* docs(network-flows): make MDX-safe for the learn deploy preview The Network Flows ingest produced four MDX 3 build failures on Netlify when learn rendered the new section. Three were `<placeholder>`-style patterns in metadata.yaml description fields: - aws_ip_ranges: `<aws-region>` and `<service-name>` - gcp_ip_ranges: `<service>` and `<scope>` - generic_json-over-http_ipam: `/api/<app>/subnets/` MDX 3 lexes `<word>` as a JSX open tag and demands a matching close. Inline code wrapping is the standard fix per the learn ingest escape battery (rule 4 preserves inline code). Wrapped each placeholder in backticks at the metadata.yaml source and re-ran gen_integrations.py to regenerate the three integration cards. The fourth was `<100 minutes` in retention-querying.md (`<` followed by a digit is parsed as JSX and rejected with `Unexpected character '1' before name`). Rephrased to "under 100 minutes". * skills: document MDX gotchas exposed by the netflow-plugin ingest The 2026-05-07 netflow-plugin learn ingest deploy preview surfaced three MDX 3 patterns that the existing escape battery does not cover. Capture them so the next author/agent does not repeat the round-trip: learn-site-structure/mdx-rules.md - New "Patterns that the escape battery does NOT cover" section under rule 5: `<word>` placeholders, `<` + digit, `Type<Param>` generics. - Spell out the three safe options in priority order (backticks, rephrase, backslash escape) with the real-world examples that triggered each. - Three new rows in the "What survives, what doesn't" table. learn-site-structure/pitfalls-and-gotchas.md - New entries below the existing `<= %< <->` near-variants warning, each with the literal MDX error message and the source-file/line context where it bit us. integrations-lifecycle/gotchas.md - New "metadata.yaml prose lands in MDX" entry: anything in description/setup/troubleshooting/related-resources flows through gen_integrations.py -> per-integration `.md` -> learn ingest -> MDX build, and netdata CI does NOT validate this; the next learn ingest deploy preview is what catches it. Lists the seven patterns that break, the fix for each, and a practical author-side recipe. - Cross-references the learn-site-structure entries so authors can see the consumer side too.