fix(readme.md): reorder installation steps in README.md

[amilamen]

markdown-it build requires dependencies in web_core like "@a2ui/web_core": "file:../../web_core"

Description

markdown-it build requires dependencies in web_core like "@a2ui/web_core": "file:../../web_core".
Without that, npm run build on markdown-it project failed.

Pre-launch Checklist

• I signed the CLA.
• I read the Contributors Guide.
• I read the Style Guide.

If you need help, consider asking for advice on the discussion board.

[gemini-code-assist]

Code Review

This pull request correctly reorders the installation steps in the README.md to address a dependency issue. However, the cd commands were not updated to reflect the new order, which breaks the sequence of shell commands. I've provided a review comment with a suggested fix for the changed lines and a note about a necessary follow-up change to make the instructions work correctly.

[gemini-code-assist]

While the intention to reorder the build steps is correct, simply swapping the blocks has broken the directory navigation, as the cd commands are relative. The cd paths are now incorrect and will cause the setup instructions to fail.

This suggestion corrects the paths for building web_core and then markdown-it.

Please note that the next step for building the 'Lit renderer' will also need its cd command updated to be relative to the new working directory (e.g., cd ../../lit).

Suggested change

	# Install and build the Web Core library
	cd ../../web_core
	npm install
	npm run build
	# Install and build the Web Core library
	cd ../../web_core
	# Install and build the Markdown renderer
	cd renderers/markdown/markdown-it
	npm install
	npm run build
	# Install and build the Web Core library
	cd renderers/web_core
	npm install
	npm run build
	# Install and build the Markdown renderer
	cd ../markdown/markdown-it
	npm install
	npm run build