feat(zephyr-astro-integration): add ZE_PUBLIC dynamic env rewrite support

[ryok90]

What's added in this PR?

• Adds an Astro-side Vite sub-plugin (with-zephyr-astro-env) through astro:config:setup so Astro follows the same ZE_PUBLIC_* runtime behavior as the existing Vite flow.
• Mirrors ZE_PUBLIC_* variables from loaded env files into process.env (without overwriting pre-set values) for manifest/runtime consistency.
• Rewrites process.env.ZE_PUBLIC_* and import.meta.env.ZE_PUBLIC_* reads to the virtual manifest module and resolves the generated env:vars:<app_uid> specifier to /zephyr-manifest.json in development and an external import in build.
• Extends Astro integration tests to cover hook registration and plugin injection.

Screenshots

• N/A (behavioral/runtime integration change)

What's the issues or discussion related to this PR ?

• Astro integration previously did not replicate ZE_PUBLIC_* dynamic env rewriting behavior already implemented in the Vite plugin path.
• This created inconsistent runtime env handling across bundlers; this PR aligns Astro behavior with the established Zephyr Vite implementation.

What are the steps to test this PR?

1. Run pnpm nx test zephyr-astro-integration.
2. In an Astro app using withZephyr, define one or more ZE_PUBLIC_* vars in .env.
3. Reference these vars via either process.env.ZE_PUBLIC_* or import.meta.env.ZE_PUBLIC_* in app code.
4. Build/serve and verify values resolve through Zephyr manifest runtime flow.

Documentation update for this PR (if applicable)?

• Not yet. If required, I can open a docs PR in zephyr-documentation to describe Astro parity for ZE_PUBLIC_* behavior.

(Optional) What's left to be done for this PR?

• Add an end-to-end Astro fixture test that asserts transformed output contains the virtual manifest import and ZE_PUBLIC_* rewrites.

(Optional) What's the potential risk and how to mitigate it?

• Risk: introducing Vite plugin behavior into Astro could affect transform ordering in uncommon project setups.
• Mitigation: plugin is scoped to ZE_PUBLIC_* references only, skips node_modules, and is covered by unit tests; further mitigate with fixture/e2e coverage.

(Required) Pre-PR/Merge checklist

• I have added/updated/opened a PR to documentation to cover this new behavior
• I have added an explanation of my changes
• I have written new tests (if applicable)
• I have tested this locally (standing from a first time user point of view, never touch this app before)
• I have/will run tests, or ask for help to add test

[github-actions]

🚀 Preview Environment Ready!

Name	Status	URL
astro-blog	✅ Active	https://testuser-45754-astro-blog-zephyr-packages-zephyrc-d347001... ↗

Details:

• Latest Commit: 398006d
• Created at: 4/30/2026, 5:42:02 PM