Chore/updated docs

[gitsad]

What does this PR do?

Overhauls the demo app UI, enriches the docs section.

Demo & branding

• New SVG logo — transparent molecular hexagon symbol with pink→teal gradient and vector MDMA letterforms (SF NS Bold, baked as paths)
• Logo integrated into top nav header and favicon; added to README alongside updated hero GIF (mdma-3.gif) and Docs link
• Home dashboard reordered: Docs promoted as a featured full-width card; title changed to "MDMA" with new tagline

Docs section

• Packages nav now has sub-items linking to individual package detail pages (install command, purpose, GitHub link, see-also cross-links)
• mdma-runtime package page includes a live action log demo
• mdma-parser page explains the parse pipeline with Input / Output AST examples
• Prompt Matrix extended with MDMA_AGENT table (calls when needed / skips when not needed / multi-turn) and In Progress section for MDMA_FIXER and MDMA_REVIEWER
• Agentic Workflow example rewritten to show MDMA as one tool among many (not the only tool)
• Introduction "What is MDMA?" rewritten as prose; footnote added linking to Mobile Reality

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing behavior to change)
• Refactor (no functional change)
• Documentation
• CI / tooling