feat: UI/UX layout enhancements, list sorting, and theme-aware SVG propagation

[ryanbaumann]

This PR applies the approved UI/UX layout tweaks and resolves field note sorting and image themes:

UI/UX Layout Enhancements

• Increased macro whitespace around the hero block and main sections via fluid clamp() values.
• Implemented responsive typography scaling for the hero intro (.lede) and stats (.hero-stats dd).
• Added an elevated, snappy interaction hover state to .card grid items.

Content Logic & Design System Fixes

• Updated SSG sorting logic for Field Notes to always use chronological order by default, decoupling the pinned homepage card (order metadata) from the main /writing/ listing index.
• Fixed an issue where theme-aware SVG images embedded via <img> tags failed to respond to the site's explicit light/dark toggles. By injecting color-scheme into the host html[data-theme] CSS block, embedded SVGs with internal media queries correctly inherit the explicit color mode.