Fix book_chapter.yml: write chapter draft before char-state extraction

Chapter_N_draft doc step was placed after PASS 3 think, so last_text()
returned char state (3151 chars) instead of the actual chapter from SELF-CHECK.
Moved doc step to immediately after step 2 (SELF-CHECK).

New step order: 0-think, 1-think, 2-think(selfcheck), 3-doc(draft),
4-think(charstate), 5-rag_write, 6-doc(charstate), 7-package, 8-close

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

templates/book_chapter.yml

@@ -251,6 +251,10 @@ steps:
         verbatim everywhere else). Start the chapter directly with the chapter title
         and first line. No preamble or commentary within the chapter text.
 
+  # Commit chapter draft now — last_text() = self-check output (step 2). Must come before
+  # PASS 3 think so the character-state extraction does not overwrite last_text().
+  - type: document
+    filename: "Chapter_{chapter_number}_draft"
 
   - type: think
     hint: |
@@ -299,8 +303,6 @@ steps:
 
   - type: document
     filename: "character-state-{chapter_ref}"
-  - type: document
-    filename: "Chapter_{chapter_number}_draft"
 
   - type: package
     max_tokens: 12000