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/checklists/world-building-continuity-checklist.md

@@ -0,0 +1,16 @@
+# ------------------------------------------------------------
+# 2. World‑Building Continuity Checklist
+# ------------------------------------------------------------
+---
+checklist:
+  id: world-building-continuity-checklist
+  name: World‑Building Continuity Checklist
+  description: Ensure geography, cultures, tech/magic rules, and timeline stay coherent.
+items:
+  - "[ ] Map geography referenced consistently"
+  - "[ ] Cultural customs/laws remain uniform"
+  - "[ ] Magic/tech limitations not violated"
+  - "[ ] Historical dates/events match world‑guide"
+  - "[ ] Economics/politics align scene to scene"
+  - "[ ] Travel times/distances are plausible"
+...