Add scale-up SFT packages and fix chapter browsing/ordering

Merge the 433-package scale-up SFT (8 additional untrained books) into
the existing 208-package browser, tagged with book title and normalized
train/holdout split. Add a Book dropdown per author, with a badge on
each package showing which book it came from.

Also fixes chapter grouping/ordering for the new books:
- Vox Day: split POV-name chapter labels when the same character
  recurs across separate, non-adjacent chapters (detected via the
  pipeline's own STORY segmentation resets), ordered by book_region
  as a coarse book-order approximation.
- Nuttall: sort spelled-out chapter numbers ("Chapter-Twenty-Three")
  numerically instead of alphabetically.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

README.md

@@ -17,8 +17,14 @@ https://claude.ai/code/artifact/d3415f56-3f9b-40de-aa70-ac0992549ced
   [llama.cpp](https://github.com/ggml-org/llama.cpp)) that `voice-bench.html`
   sends generation requests to.
 
-The 208 training/holdout packages themselves are already embedded inside
-`voice-bench.html` — nothing else needs downloading for browsing.
+All 641 training/holdout packages across both SFT rounds are already
+embedded inside `voice-bench.html` — nothing else needs downloading for
+browsing. That's the original 208-package SFT (one book per author: *A Sea
+of Skulls*, *Hour of the Wolf*) plus the 433-package scale-up SFT (four
+more books per author, all held out of both CPT and the original SFT). Use
+the **Book** dropdown to switch between them; each package's card also
+shows which book it came from and whether it was used in training or held
+out.
 
 ## One-time setup (per machine)