cover page: share header bar, drop redundant title, dotfill barèmes

feat: optional cover/intro page

fix: \textit{} breaks longtable on \begin{cases}; use {\itshape ...} instead

fix: pdflatex UTF-8 decode crash + downscale uploads

4 features: PDF input, header layout, changelog, version history

header: school centered alone, teacher above doc type

fix: align header/body widths + repeat full header on all pages

fix: header override before compile + no phantom figures

fix header override + add "Appliquer l'en-tête" button + progress bar

editable header fields with defaults

auth: password-only login (no username field)

add password protection via APP_PASSWORD env var

fix: auto page numbering 1/N on every page

structured data architecture: template + tool use

fix: stale preview-*.png leaking page count after modification

figure-aware pipeline with iterative self-verification

generic UI text and scrub README/app.py

initial deploy

initial commit