[codex] remove rendered key attributes from tags

[Sean-Kenneth-Doherty]

Summary

• Remove the React-only key attribute from project tag wrappers in ProjectCard.astro.

Why

Astro does not treat key={tag} as a framework diffing hint in this server-rendered markup, so it was emitted into the final HTML as key="..." on every project tag wrapper. Removing it keeps the generated markup cleaner and avoids invalid/noisy attributes.

Validation

• pnpm build
• Confirmed built dist/index.html no longer contains <div key="..."> project tag wrappers
• git diff --check

Contributes to #347.

[Sean-Kenneth-Doherty]

Withdrawing this to keep the contribution queue focused on the highest-signal fixes. I opened too many small slices here, and this one is less important than the concrete broken-link, security, workflow, rendering, and accessibility fixes that remain open.