Show the actual PDF-to-notes lineage in the landing hero

[jay0n9]

What changed

• Replace the landing Hero's abstract Read/Understand/Connect cycle with one real public lineage: source PDF → generated paper-note draft → four generated concept-note drafts.
• Keep generated filenames visible while the shared preview defaults to their source-checked sibling files, with direct links to both versions.
• Render the actual first page of the unchanged CC BY 4.0 source PDF and keep DOI, attribution, and manifest beside the demo.
• Synchronize concept navigation between the embedded Markdown viewer and the outer lineage, including keyboard navigation and responsive mobile layout.
• Mark preview images as binary so Git never applies line-ending normalization.

Verification

• Chrome at 320, 390, 560, 561, 760, 1120, and 1200 px: no horizontal overflow or console/network errors.
• PDF, paper note, all four concept notes, generated-draft links, iframe wiki-link synchronization, and EN/KO switching exercised.
• All 14 manifest artifacts verified against their recorded byte counts and SHA-256 values.
• node --check for both modified JavaScript files, CSS/copy-key checks, Python compileall, and git diff --check passed.