chore: add Cloud-specific dev environment setup

[yuler]

Summary

Sets up the Cursor Cloud development environment for this Astro personal site.

Changes

• AGENTS.md: Added ## Cursor Cloud specific instructions section with non-obvious caveats for future cloud agents (Node v24 via nvm, sharp build approval, dev server config, no external services required, no test framework).
• package.json: Added pnpm.onlyBuiltDependencies to allow sharp and esbuild postinstall scripts to run non-interactively, avoiding the interactive pnpm approve-builds prompt.

Verification

• pnpm check — 0 errors, 0 warnings
• pnpm build — 27 pages built successfully with image optimization
• pnpm dev — Dev server running on port 4321, homepage / blog posts / workouts pages all render correctly

  

[gemini-code-assist]

Code Review

This pull request introduces Cursor Cloud specific instructions to AGENTS.md and configures pnpm.onlyBuiltDependencies in package.json for sharp and esbuild. The review feedback suggests improving the Node.js version management by using nvm use without a hardcoded version to automatically reference .nvmrc, and adding a trailing newline to package.json for POSIX compliance.

[gemini-code-assist]

To make this instruction more robust and prevent it from becoming outdated if .nvmrc is updated, you can use nvm use without specifying the version number. It will automatically pick up the version from the .nvmrc file.

Suggested change

	- **Node.js**: `.nvmrc` specifies `v24`. Use `source ~/.nvm/nvm.sh && nvm use 24` before running any commands.
	- **Node.js**: `.nvmrc` specifies `v24`. Use `source ~/.nvm/nvm.sh && nvm use` before running any commands.

[gemini-code-assist]

It's a good practice to end files with a newline character. This aligns with POSIX standards for text files and can prevent potential issues with some command-line tools that process text files.

Suggested change

	}
	}