build(web): upgrade to Astro v6

[parse]

Summary

• Upgrade astro from v5.18.0 to v6.0.0, @astrojs/starlight to 0.38.1, starlight-blog to 0.26.0, and starlight-links-validator to 0.20.0
• Remove the Zod alias hack from astro.config.mjs — Astro v6 bundles Zod 4 natively, so the workaround for root zod@4 conflicts is no longer needed
• Remove redundant output: 'static' (default since Astro v5)

Test plan

• npm run typecheck --workspace=packages/web — 0 errors
• npm run check:ci --workspace=packages/web — astro check + build pass, all links valid
• astro preview smoke test — all key pages return 200 with valid HTML
• CI passes

Summary by CodeRabbit

• Chores
  • Updated core dependencies to latest versions, including Astro framework upgrade
  • Streamlined build configuration by removing unused settings

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 21518881-55a8-4b93-bcc0-6750f16531bf

📥 Commits

Reviewing files that changed from the base of the PR and between d741392 and 1d37120.

⛔ Files ignored due to path filters (1)

• package-lock.json is excluded by !**/package-lock.json

📒 Files selected for processing (2)

• packages/web/astro.config.mjs
• packages/web/package.json

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📝 Walkthrough

Walkthrough

Astro dependencies are updated to newer versions including a major bump to v6.0.0, and custom Zod resolution logic along with static output configuration are removed from the Astro config file.

Changes

Cohort / File(s)	Summary
Configuration cleanup packages/web/astro.config.mjs	Removed custom Zod resolution logic (dynamic require and vite alias), and removed output: 'static' configuration. Site and integrations sections preserved.
Dependency updates packages/web/package.json	Updated four dependencies: @astrojs/starlight (^0.37.7 → ^0.38.1), astro (^5.18.0 → ^6.0.0), starlight-blog (^0.25.3 → ^0.26.0), starlight-links-validator (^0.19.2 → ^0.20.0).

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 Dependencies dance to versions new,
Zod's resolve bids its adieu,
Static output cast away,
Astro six greets the day! ✨

✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch chore/upgrade-astro-v6

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