chore: update Astro templates to latest versions and prepare for v6

[zeke]

This PR updates the Astro templates to the latest stable versions and prepares them for Astro 6 compatibility.

Astro 6 is currently in beta (released today, Jan 13, 2026). These changes ensure the templates:

• Use the latest stable Astro 5.x versions
• Are forward-compatible with Astro 6 when it releases
• Document Node.js 22 requirement (Astro 6 drops Node 18/20 support)

References

• Astro 6 Upgrade Guide
• z import deprecation

Testing locally

gh pr checkout 897 --repo cloudflare/templates

# Test astro-blog-starter-template
cd astro-blog-starter-template
npm install
npm run build

# Test saas-admin-template
cd ../saas-admin-template
npm install
npm run build

[craigsdennis]

👍 Like the warnings

[deloreyj]

@zeke Looks like the lockfiles are out of date now. Can you run a pnpm install and pnpm fix:lockfiles from the top level of the repo please?

[zeke]

@zeke Looks like the lockfiles are out of date now. Can you run a pnpm install and pnpm fix:lockfiles from the top level of the repo please?

Done! 6beb069 -- that changed a bunch of lock files, not just the top-level stuff. Is that expected?

[deloreyj]

@zeke Looks like the lockfiles are out of date now. Can you run a pnpm install and pnpm fix:lockfiles from the top level of the repo please?

Done! 6beb069 -- that changed a bunch of lock files, not just the top-level stuff. Is that expected?

Yeah, it changed the lockfiles for each of the templates you changed, the top-level lockfile for the monorepo, and the templates.json file that contains a hash of the package.json to ensure that lockfiles and package.json files stay in sync.

[github-actions]

template	name	version	latestVersion	isDevDependency
saas-admin-template	@types/react	19.2.7	19.2.8	false
saas-admin-template	lucide-react	0.555.0	0.562.0	false
saas-admin-template	react	19.2.1	19.2.3	false
saas-admin-template	react-dom	19.2.1	19.2.3	false
saas-admin-template	react-hook-form	7.66.1	7.71.1	false
saas-admin-template	tailwindcss	^3.4.0	4.1.18	false
saas-admin-template	zod	4.1.13	4.3.5	false
saas-admin-template	wrangler	4.56.0	4.59.2	true
astro-blog-starter-template	wrangler	4.56.0	4.59.2	true

[github-actions]

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