feat: unified loading experience + cleanup dead code

chore: remove 23 dead code files (~2,350 lines)

chore: clean up repo for open source release

fix: close intro modal when clicking overlay background

fix: restore data-font attribute for tooltip/hover detection

fix: match sprite symbol IDs (font_id + '_a' suffix)

perf: use sprite SVG instead of 1200 individual fetches + add loading spinner

feat: switch to source-based deployment with HF build step

feat: deploy FontMap with FontCLIP pipeline

feat: FontMap with FontCLIP pipeline, category colors, and interactive map