feat: add optional code linting tools and perform a lint pass

[piprees]

What has changed:

• Adding guidance on accessibility/style and updating all posts to use the new accessible <figure>. Made sure all images have a valid alt attribute.
• Added <figure-audio> to allow in-page audio playback and added it to Gethin's AI audio post. Renamed generic podcast name to match blog post so it has a unique name.
• Added code quality tools section to README, configured the repo to use them, and default settings for VSCode and IntelliJ to automatically use them if installed. Also added Hugo tasks to IDEs. Not added to CI/Git Hook so they remain optional.
• Added width and height to all images to improve CLS, and did a pass on images to reduce the massive ones down to a reasonable sizes and converted screenshots as png to jpg, compressed the SVG. This figure also uses decoding="async" for improved rendering performance.
• Made sure all code blocks have the right language.

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No new content.

Depends on this PR being merged: #40