refactor: make ARNES external-repo based with ticket publish flow

spec/sdd-bdd-guide.md

@@ -1,4 +1,4 @@
-# SDD/BBD Guide — System Design Document & Behavior Driven Development
+# SDD/BDD Guide — System Design Document & Behavior Driven Development
 
 Guía para crear y mantener SDD (System Design Document) y BDD (Behavior Driven Development) specs dentro del framework ARNES.
 
@@ -25,10 +25,13 @@ spec/
 │   ├── architecture.md
 │   ├── components/
 │   └── decisions/
-└── bdd/              # Behavior Driven Development
+└── bdd/              # Behavior Driven Development source-of-truth
     ├── README.md
-    ├── features/
-    └── step_definitions/
+    └── features/
+
+features/             # optional executable BDD runner assets
+├── behave.ini
+└── steps/
 ```
 
 ---
@@ -152,6 +155,11 @@ spec/bdd/features/
 │   └── purchase.feature
 └── common/
     └── error-handling.feature
+
+features/
+├── behave.ini
+└── steps/
+    └── login_steps.py
 ```
 
 ### Tags para trazabilidad
@@ -224,8 +232,10 @@ Tags disponibles:
 
 ```bash
 # Estructura
+spec/bdd/features/
+└── login.feature
+
 features/
-├── login.feature
 └── steps/
     └── login_steps.py
 
@@ -237,8 +247,10 @@ behave features/
 
 ```bash
 # Estructura
+spec/bdd/features/
+└── login.feature
+
 features/
-├── login.feature
 └── step_definitions/
     └── login_steps.js