v2.0.0: Modularize project into single-responsibility packages

Replaced monolithic modules/ package with a clean architecture:

- core/       config.py, utils.py
- ai/         models.py (ResilientModel), setup.py (init_models)
- story/      planner.py, writer.py, editor.py, style_persona.py, bible_tracker.py
- marketing/  cover.py, blurb.py, fonts.py, assets.py
- export/     exporter.py
- web/        app.py (Flask factory), db.py, helpers.py, tasks.py, routes/{auth,project,run,persona,admin}.py
- cli/        engine.py (run_generation), wizard.py (BookWizard)

Flask routes split into 5 Blueprints; all templates updated with blueprint-
prefixed url_for() calls. Dockerfile and docker-compose updated to use
web.app entry point and new package paths.

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

templates/admin_style.html

@@ -5,7 +5,7 @@
     <div class="col-md-8">
         <div class="d-flex justify-content-between align-items-center mb-4">
             <h2><i class="fas fa-spell-check me-2 text-primary"></i>Style Guidelines</h2>
-            <a href="{{ url_for('admin_dashboard') }}" class="btn btn-outline-secondary">Back to Admin</a>
+            <a href="{{ url_for('admin.admin_dashboard') }}" class="btn btn-outline-secondary">Back to Admin</a>
         </div>
 
         <div class="card shadow-sm">
@@ -36,7 +36,7 @@
                         <button type="submit" class="btn btn-primary btn-lg">
                             <i class="fas fa-save me-2"></i>Save Guidelines
                         </button>
-                        <button type="submit" formaction="{{ url_for('optimize_models') }}" class="btn btn-outline-info w-100 mt-2">
+                        <button type="submit" formaction="{{ url_for('admin.optimize_models') }}" class="btn btn-outline-info w-100 mt-2">
                             <i class="fas fa-magic me-2"></i>Auto-Refresh with AI
                         </button>
                     </div>