Split long page text into 1500-char chunks before calling Ollama, then
mean-pool the per-chunk vectors into one page vector. Removes the hard
6000-char slice that still caused 500s on dense markdown/table pages.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Pads nomic-embed-text's 768 dims to 1024 zeros so a later 1024-dim model
swap is a re-embed, not a migration (per master spec).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>