Add Creative Writing expansion pack (#414)

* Add Creative Writing expansion pack
- 10 specialized writing agents for fiction and narrative design
- 8 complete workflows (novel, screenplay, short story, series)
- 27 quality checklists for genre and technical validation
- 22 writing tasks covering full creative process
- 8 professional templates for structured writing
- KDP publishing integration support

* Fix bmad-creative-writing expansion pack formatting and structure

- Convert all agents to standard BMAD markdown format with embedded YAML
- Add missing core dependencies (create-doc, advanced-elicitation, execute-checklist)
- Add bmad-kb.md customized for creative writing context
- Fix agent dependency references to only include existing files
- Standardize agent command syntax and activation instructions
- Clean up agent dependencies for beta-reader, dialog-specialist, editor, genre-specialist, narrative-designer, and world-builder

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Co-authored-by: Brian <bmadcode@gmail.com>

expansion-packs/bmad-creative-writing/tasks/create-draft-section.md

@@ -0,0 +1,19 @@
+# ------------------------------------------------------------
+# 4. Create Draft Section (Chapter)
+# ------------------------------------------------------------
+---
+task:
+  id: create-draft-section
+  name: Create Draft Section
+  description: Draft a complete chapter or scene using the chapter-draft-tmpl.
+  persona_default: editor
+inputs:
+  - story-outline.md | snowflake-outline.md | scene-list.md | release-plan.md
+parameters:
+  chapter_number: integer
+steps:
+  - Extract scene beats for the chapter.
+  - Draft chapter using template placeholders.
+  - Highlight dialogue blocks for later polishing.
+output: chapter-{{chapter_number}}-draft.md
+...