Upgrade site to Astro v6 and Starlight v0.38

[mkaput]

Motivation

• Starlight 0.38.x requires upgrading Astro to v6 and aligning official integrations to avoid runtime and build incompatibilities.
• Refreshing dependencies and the lockfile ensures the local dependency graph matches Starlight’s supported peer versions.
• The goal is to bring the docs stack up-to-date while keeping content collections working with the new Content Layer APIs.

Description

• Bumped runtime dependencies in package.json: astro -> ^6.1.2, @astrojs/starlight -> ^0.38.2, and starlight-llms-txt -> ^0.8.0, and bumped @astrojs/check -> ^0.9.8 in devDependencies.
• Updated the project lockfile (bun.lock) to capture resolved Astro v6 / Starlight v0.38 dependency graph and peer changes.
• No code migrations to content collections were required because the project already uses Content Layer loaders (docsLoader() and file()), and imports use astro/zod.
• Committed the package.json and bun.lock updates and prepared the PR metadata.

Testing

• Ran bun links --check and link validation passed.
• Ran bun lint (which runs astro check) and it failed in this environment because Astro v6 requires Node >=22.12.0 while the container provides Node v20.19.6.
• Dependency installation via bun add completed and the lockfile was refreshed successfully.
• No further automated tests were executed in this environment due to the Node version limitation.

---

Codex Task

[GrzywN]

Upgraded outdated minor package versions:

agentic-engineering on  codex/upgrade-website-to-astro-v6 [$!] via 🥟 v1.3.11
❯ bun outdated
bun outdated v1.3.11 (af24e281)
[0.03ms] ".env"
┌──────────────────┬─────────┬────────┬────────┐
│ Package          │ Current │ Update │ Latest │
├──────────────────┼─────────┼────────┼────────┤
│ astro            │ 6.1.2   │ 6.1.3  │ 6.1.3  │
├──────────────────┼─────────┼────────┼────────┤
│ @types/bun (dev) │ 1.3.10  │ 1.3.11 │ 1.3.11 │
├──────────────────┼─────────┼────────┼────────┤
│ typescript (dev) │ 5.9.3   │ 5.9.3  │ 6.0.2  │
└──────────────────┴─────────┴────────┴────────┘


agentic-engineering on  codex/upgrade-website-to-astro-v6 [$!] via 🥟 v1.3.11
❯ bun update
[0.20ms] ".env"
bun update v1.3.11 (af24e281)

↑ @types/bun 1.3.10 → 1.3.11
↑ astro 6.1.2 → 6.1.3

+ @astrojs/check@0.9.8
+ prettier@3.8.1
+ prettier-plugin-astro@0.14.1
+ typescript@5.9.3 (v6.0.2 available)
+ @astrojs/starlight@0.38.2
+ @std/csv@1.0.6
+ sharp@0.34.5
+ starlight-llms-txt@0.8.0

447 packages installed [944.00ms]

agentic-engineering on  codex/upgrade-website-to-astro-v6 [$!] via 🥟 v1.3.11
❯ bun outdated
bun outdated v1.3.11 (af24e281)
[0.04ms] ".env"
┌──────────────────┬─────────┬────────┬────────┐
│ Package          │ Current │ Update │ Latest │
├──────────────────┼─────────┼────────┼────────┤
│ typescript (dev) │ 5.9.3   │ 5.9.3  │ 6.0.2  │
└──────────────────┴─────────┴────────┴────────┘

agentic-engineering on  codex/upgrade-website-to-astro-v6 [$!] via 🥟 v1.3.11
❯

[GrzywN]

LGTM, I upgraded minor versions as we still had outdated packages.

[mkaput]

@GrzywN can you fix CI please? 🙏🏻