Release v1.3.2: rendering safety and documentation quality

[ikelaiah]

What changed

• Keep generated HTML out of image descriptions and preserve exact link targets.
• Publish single-site builds only after rendering succeeds, preserving the previous site on failure.
• Rebuild previews when configured logo, banner or CSS assets change; leave outline disclosure state under reader control.
• Add an architecture diagram and improve renderer, contribution and release guidance.
• Update package metadata, version history and workflow pins for v1.3.2.

Verification

• 329 unit and qualification tests pass.
• ruff check ., documentation check, strict audit and 41-page site build pass.
• Wheel and sdist for v1.3.2 both pass artifact qualification.
• Local headless Chrome checks covered 32 style, colour-mode and viewport combinations plus keyboard and outline behaviour.

Follow-up findings

The review report records two pre-existing items for separate work: README identity when adopting projects contain docs/README.md, and preserving the previous complete output if a later release fails during build-all.