Record the switch from the in-house SDD workflow to Superpowers

[Smana]

Summary

cloud-native-ref switched from its in-house Spec-Driven Development workflow to Superpowers (Smana/cloud-native-ref#1764, merged 2026-08-18). Two articles in the Agentic AI series document the old workflow; this brings them up to date.

Changes

ai-coding-agent (FR + EN) — the article carrying the "My SDD variant for Platform Engineering" section, with its constitution, four review personas, /spec /clarify /validate skill table and eight screenshots.

• An Update 2026-08-18 notice after the front matter, matching the convention already used in terraform-controller and crossplane_composition_functions.
• A short line inside the "My SDD variant" notice, so a reader arriving mid-article from a search result is not misled.
• The section body is not rewritten. It remains an accurate account of what was built and ran for months, and the reasoning behind it — platform constitution, review personas, verification against a real cluster — survived the switch. Only the mechanism changed.
• The constitution link is repointed from docs/specs/constitution.md to docs/platform-constitution.md, which the migration moved. Verified against main: the new path resolves, the old one 404s.
• Superpowers added to the article's "Spec-Driven Development" reference list, which named Spec Kit, OpenSpec and BMAD but not the tool that actually won.

ai-coding-tips — the French version already said Superpowers was the preferred SDD flavour; the English translation was missing the article's entire opening section (## Mon utilisation actuelle de Claude Code), so an English reader never saw it.

• That section is translated and inserted into the English post — MCP list, skills / subagents / SDD bullets, and the mise en abyme notice. Both languages now report 13 ## sections.
• The SDD bullet in both languages now records the completed switch rather than a current preference.
• French "Article vivant" date refreshed to 18 août 2026.

Validation

• hugo --gc --minify → exit 0, 89 EN / 67 FR pages, no shortcode errors.
• Both notices render in both languages; the rendered output contains docs/platform-constitution.md and no docs/specs/constitution.md.