fix: use Mintlify MDX components in helm chart docs templates

[dangrondahl]

Summary

• Add mintlify.install and mintlify.customCA template overrides in _mintlify_templates.gotmpl so the Mintlify output uses <Steps>, <Note>, <Info>, <Warning> components while the plain markdown README stays unchanged
• Auto sentence-case <ParamField> descriptions (capitalize first word, ensure trailing period)
• Escape angle brackets in values.yaml descriptions (<instance_name> → INSTANCE_NAME) to prevent JSX parse errors in MDX

Closes #853

Test plan

• Run cd charts/k8s-reporter && helm-docs --template-files README.md.gotmpl,_templates.gotmpl and verify README.md has no Mintlify components
• Run cd charts/k8s-reporter && helm-docs --template-files MINTLIFY.md.gotmpl,_templates.gotmpl,_mintlify_templates.gotmpl and copy output to docs repo as helm/k8s_reporter.mdx
• Verify the MDX page renders in Mintlify without JSX parse errors

[claude]

Claude finished @dangrondahl's task in 2m 48s —— View job

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PR Review: fix: use Mintlify MDX components in helm chart docs templates

• Run static analysis (build, vet, mod tidy)
• Review changed files
• Post inline comments on specific issues
• Post summary review

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Static Analysis

All checks pass: go build ./..., go vet ./..., go mod tidy — no issues.

Summary

Clean, well-structured PR. The approach of creating dedicated mintlify.install and mintlify.customCA templates that mirror the plain-markdown counterparts but wrap content in MDX components (<Steps>, <Note>, <Info>, <Warning>) is the pragmatic solution given Go template limitations.

What works well:

• The values.yaml angle-bracket escaping (<instance_name> → INSTANCE_NAME) prevents JSX parse errors at the source, and the backtick-wrapping of {name, value} etc. improves readability in both README and MDX outputs
• The sentence-casing logic in mintlify.paramField (capitalize first char, ensure trailing period) is correctly guarded against empty descriptions and handles edge cases like backtick-prefixed or acronym-prefixed text
• The template split is clean — MINTLIFY.md.gotmpl picks mintlify.* templates while README.md.gotmpl stays on extra.*, keeping the two output paths independent

One observation (not a blocker):

• The mintlify.install / mintlify.customCA templates duplicate nearly all the prose from extra.install / extra.customCA — only the markup differs. Future content changes will need updates in both places. Left an inline comment suggesting a brief note at the top of the file for future maintainers.

No bugs, security issues, or correctness concerns found. LGTM.