chore: consolidated dependency updates (Dependabot #17-#31)

[eterna2]

This PR consolidates 14 individual Dependabot updates into a single PR.

Included Updates:

• Website (npm): Next.js 16.2.3, React 19.2.5, ESLint 10.1.0, and @types/node 25.6.0.
• Python (pip): pytest 9.0.3, pytest-asyncio 1.3.0, respx 0.23.1, and hypothesis 6.151.12.
• GitHub Actions: pypa/gh-action-pypi-publish v2.0.0 and actions/download-artifact v8.0.1.

Technical Notes & Constraints:

• PyO3 & serde_jcs: Major bumps to PyO3 (0.28.3) and serde_jcs (0.2.0) were excluded because they require Rustc 1.83+ and Cargo Edition 2024 respectively, which are currently incompatible with the host environment (Rustc 1.81.0).
• Available Versions: Some Python dependencies were pinned to the highest available registry versions (e.g. pytest 9.0.3) despite Dependabot suggesting slightly higher versions that were not yet resolvable for all supported Python environments.

Verified with moon run kest-core-python:test and website build.

[github-actions]

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Deployment	URL
This PR	https://eterna2.github.io/kest/preview/chore-consolidated-dep-updates-20260411/
stable (current main)	https://eterna2.github.io/kest/stable/
All versions	https://eterna2.github.io/kest/
Branch	chore/consolidated-dep-updates-20260411
Commit	2553bfa750165c17d66e8aac061222abcae3db61

Preview updates automatically on every push to this branch. It will be removed when this PR is closed.