fix(images): correct HiDPI responsive image rendering

[flsobral]

Summary

• Corrects visible softness and stretching affecting home_homeapp and home_tecdet on HiDPI displays while preserving the existing homepage design and responsive behavior.
• Confirms the generated image aspect ratios were already correct; the regression came from insufficient physical-pixel resolution at the rendered CSS size.
• Adds appropriately larger 1200 px and 1600 px responsive variants for Tecdet and restores automatic height handling.
• Keeps Home Automation’s real 1024 px source and caps normal rendering at 512 CSS px to avoid artificial upscaling when no higher-resolution source is available.
• Updates the asset-optimization guidance to size responsive candidates from CSS width × target DPR and to avoid source upscaling.

Validation

• SPDX and repository-wide license checks
• Astro static checks and production build
• Generated markup, dimensions, candidates, aspect ratios, and asset-budget checks
• Headless desktop validation at 1440 CSS px / DPR 2 and mobile validation at 390 px

The change retains AVIF/WebP delivery, expected aspect ratios, content order, visual design, and mobile stacking.