feat: migrate to PostgreSQL + SQLAlchemy ORM, rebrand to Nexus Autoparts

- Migrate from SQLite to PostgreSQL with normalized schema
- Add 11 lookup tables (fuel_type, body_type, drivetrain, transmission,
  materials, position_part, manufacture_type, quality_tier, countries,
  reference_type, shapes)
- Rewrite dashboard/server.py (76 routes) using SQLAlchemy text() queries
- Rewrite console/db.py (27 methods) using SQLAlchemy ORM
- Add models.py with 27 SQLAlchemy model definitions
- Add config.py for centralized DB_URL configuration
- Add migrate_to_postgres.py migration script
- Add docs/METABASE_GUIDE.md with complete data entry guide
- Rebrand from "AUTOPARTS DB" to "NEXUS AUTOPARTS"
- Fill vehicle data gaps via NHTSA API + heuristics:
  engines (cylinders, power, torque), brands (country, founded_year),
  models (body_type, production years), MYE (drivetrain, transmission, trim)

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

docs/INSTALLATION.md

@@ -1,4 +1,4 @@
-# Guía de Instalación - Autoparts DB
+# Guía de Instalación - Nexus Autoparts
 
 ## Requisitos del Sistema
 
@@ -28,10 +28,10 @@ El proyecto es compatible con:
 
 ```bash
 # 1. Clonar el repositorio
-git clone https://git.consultoria-as.com/[usuario]/Autoparts-DB.git
+git clone https://git.consultoria-as.com/[usuario]/Nexus-Autoparts.git
 
 # 2. Entrar al directorio
-cd Autoparts-DB
+cd Nexus-Autoparts
 
 # 3. Instalar dependencias
 pip install -r requirements.txt
@@ -48,8 +48,8 @@ python3 server.py
 ### Paso 1: Clonar el Repositorio
 
 ```bash
-git clone https://git.consultoria-as.com/[usuario]/Autoparts-DB.git
-cd Autoparts-DB
+git clone https://git.consultoria-as.com/[usuario]/Nexus-Autoparts.git
+cd Nexus-Autoparts
 ```
 
 ### Paso 2: Crear Entorno Virtual (Recomendado)
@@ -254,16 +254,16 @@ gunicorn -w 4 -b 0.0.0.0:8080 server:app
 
 ### Usando systemd
 
-Crear archivo `/etc/systemd/system/autoparts-db.service`:
+Crear archivo `/etc/systemd/system/nexus-autoparts.service`:
 
 ```ini
 [Unit]
-Description=Autoparts DB Dashboard
+Description=Nexus Autoparts Dashboard
 After=network.target
 
 [Service]
 User=www-data
-WorkingDirectory=/path/to/Autoparts-DB/dashboard
+WorkingDirectory=/path/to/Nexus-Autoparts/dashboard
 ExecStart=/usr/bin/python3 server.py
 Restart=always
 
@@ -274,8 +274,8 @@ WantedBy=multi-user.target
 Habilitar e iniciar:
 
 ```bash
-sudo systemctl enable autoparts-db
-sudo systemctl start autoparts-db
+sudo systemctl enable nexus-autoparts
+sudo systemctl start nexus-autoparts
 ```
 
 ### Usando Docker (Opcional)
@@ -294,8 +294,8 @@ CMD ["python3", "dashboard/server.py"]
 ```
 
 ```bash
-docker build -t autoparts-db .
-docker run -p 5000:5000 autoparts-db
+docker build -t nexus-autoparts .
+docker run -p 5000:5000 nexus-autoparts
 ```
 
 ---
@@ -319,7 +319,7 @@ pip install --upgrade -r requirements.txt
 deactivate
 
 # Eliminar directorio del proyecto
-rm -rf Autoparts-DB
+rm -rf Nexus-Autoparts
 
 # Eliminar entorno virtual (si está separado)
 rm -rf venv