docs: fix release-notes frontmatter from cubic review

[fatih-acar]

Addresses the cubic review on #9978 — the release-notes description frontmatter that the backfill drafted (added on stable) had several content errors, plus two robustness gaps in the backfill script. Fixing at the source (stable) so the corrections propagate to develop on the next sync.

Frontmatter description fixes

File	Fix
release-1_1_2.mdx	INFRAHUBPUBLICURL → INFRAHUB_PUBLIC_URL
release-1_1_6.mdx	typo cop → copy
release-1_2_1.mdx	INFRAHUBSCHEMASTRICTMODE → INFRAHUB_SCHEMA_STRICT_MODE
release-1_2_9.mdx	INFRAHUBTESTINGSCHEMASTRICTMODE / INFRAHUBSCHEMASTRICTMODE → underscored names
release-1_3_1.mdx	minvalue/maxvalue/excludedvalues → min_value/max_value/excluded_values
release-1_3_3.mdx	drop leaked <!-- vale off --> directive from the description
release-1_4_3.mdx	add missing sentence break (healthy. In the UI)
release-1_5_0.mdx	replace generic placeholder (identical to 1.4.0's) with a release-specific summary

Release-date correction (1.8.0)

• release-1_8_0.mdx: release_date corrected to 2026-03-16 (frontmatter + body table), matching the infrahub-v1.8.0 git tag. It was recorded as 2026-03-22.
• 1.8.1 is left unchanged (2026-03-19, matching infrahub-v1.8.1). cubic flagged 1.8.1 as chronologically impossible, but that was a consequence of the wrong 1.8.0 date — with 1.8.0 corrected to 03-16, the 1.8.0 → 1.8.1 → 1.8.2 (03-25) order is consistent.

Backfill script (backfill-release-frontmatter.mjs)

• --check now fails on files with no frontmatter block (previously skipped with a warning, so CI could pass on the most incomplete files).
• Descriptions are serialized with JSON.stringify so backslashes/quotes stay valid YAML (the old quoted interpolation only escaped ").

Validation

• node scripts/backfill-release-frontmatter.mjs --check — passes.
• Frontmatter of every edited file parses as valid YAML.
• node --check on the script passes.

🤖 Generated with Claude Code

---

Summary by cubic

Fixes frontmatter errors in release notes and corrects the 1.8.0 release date. Hardens the backfill script to fail on missing frontmatter and output YAML-safe descriptions.

• Bug Fixes
  • Corrected env var/parameter names and typos in release descriptions (1.1.2, 1.1.6, 1.2.1, 1.2.9, 1.3.1, 1.3.3, 1.4.3, 1.5.0).
  • Set 1.8.0 release_date to 2026-03-16 in frontmatter and the table.
  • docs/scripts/backfill-release-frontmatter.mjs: --check now fails on files without frontmatter; descriptions use JSON.stringify for YAML-safe escaping.

^{Written for commit 6f02322. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 10 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

<sub>Shadow auto-approve: would auto-approve. Fixes frontmatter typos and env-var names in release notes, corrects a release date, and hardens a validation script. All changes are bounded and clearly beneficial.

Re-trigger cubic</sub>