feat(marketing): register 3 new Flask blueprints (marketing, billing, legal)

- marketing_bp at root "/"
- billing_bp at /checkout/* (routes added in B-2.7)
- legal_bp at /legal/* (routes added in B-2.9)
- Tests verify all 3 blueprints register correctly
- Coexists with existing recordings_bp at "/" (resolved in B-1.3)

src/app.py

@@ -585,6 +585,11 @@ from src.api.api_v1 import api_v1_bp, init_api_v1_helpers
 from src.api.audit import audit_bp
 from src.api.docs import docs_bp
 
+# Marketing redesign 2026 blueprints (Phase 1: B-1.2)
+from src.marketing import marketing_bp
+from src.billing import billing_bp
+from src.legal import legal_bp
+
 # Database initialization (extracted to src/init_db.py)
 from src.init_db import initialize_database
 with app.app_context():
@@ -632,6 +637,14 @@ csrf.exempt(api_v1_bp)  # API v1 uses token auth, not CSRF
 app.register_blueprint(audit_bp)
 app.register_blueprint(docs_bp)
 
+# Marketing redesign 2026 blueprints (Phase 1: B-1.2)
+# - marketing_bp at "/" (placeholder; coexists with recordings_bp.index, resolved in B-1.3)
+# - billing_bp at /checkout/* (routes added in B-2.7 and B-2.8)
+# - legal_bp at /legal/* (routes added in B-2.9)
+app.register_blueprint(marketing_bp)
+app.register_blueprint(billing_bp)
+app.register_blueprint(legal_bp)
+
 # File monitor and scheduler initialization functions below
 
 # Startup functions (extracted to src/config/startup.py)