feat: Improve revision pipeline quality — 6 targeted enhancements (v3.1)

1. editor.py — Fix rewrite_chapter_content to use model_writer (was model_logic).
   Chapter rewrites now use the creative writing model, not the cheaper analysis model.

2. editor.py — evaluate_chapter_quality now uses keep_head=True so the evaluator
   sees the chapter opening (engagement hook, sensory anchoring) as well as the
   ending; long chapters no longer scored on tail only.

3. editor.py — Consistency analysis sampling upgraded to head+middle+tail (was
   head+tail), giving the LLM a complete view of each chapter's events.

4. writer.py — max_attempts is now adaptive: climax/resolution chapters
   (position >= 0.75) receive 3 refinement attempts; others keep 2.

5. writer.py — Polish-skip threshold tightened from 0.012 to 0.008 (1 filter
   word per 125 words vs. 1 per 83 words), so more borderline drafts are cleaned.

6. style_persona.py — Persona validation sample increased from 200 to 400 words
   for more reliable voice quality assessment.

Version bumped: 3.0 → 3.1

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

story/style_persona.py

@@ -121,7 +121,7 @@ def validate_persona(bp, persona_details, folder):
 
     sample_prompt = f"""
     ROLE: Fiction Writer
-    TASK: Write a 200-word opening scene that perfectly demonstrates this author's voice.
+    TASK: Write a 400-word opening scene that perfectly demonstrates this author's voice.
 
     AUTHOR_PERSONA:
     Name: {name}
@@ -131,7 +131,7 @@ def validate_persona(bp, persona_details, folder):
     TONE: {tone}
 
     RULES:
-    - Exactly ~200 words of prose (no chapter header, no commentary)
+    - Exactly ~400 words of prose (no chapter header, no commentary)
     - Must reflect the persona's stated sentence structure, vocabulary, and voice
     - Show, don't tell — no filter words (felt, saw, heard, realized, noticed)
     - Deep POV: immerse the reader in a character's immediate experience