Diagnosed in a real browser (playwright/chromium against the running
app + Head First SQL): the engine's book.toc held all 18 entries with
correct labels/hrefs and the tab counter even showed 380, yet zero
links rendered while the console flooded with 'Alpine Warning:
Duplicate key on x-for'.
Root cause: the drawer keyed TOC rows by item.href. PDF outline
entries frequently share the same destination (e.g. the printed TOC
page is targeted by several bookmark entries), so flattened items
carried duplicate keys — and Alpine's x-for renders NOTHING for a
duplicated key, not even the unique ones. EPUB TOCs never collided
because their hrefs are unique file paths, which is why this only
surfaced on PDFs.
Key is now href + row index (the list is static once loaded, so
positional keys are safe). Verified end-to-end in the browser: 18
entries render and the drawer populates.
john-okeefe
206db93587