add Debian 11 support

- Created dedicated modules/bullseye/` folder for legacy isolation (Debian 11 support).
- Implemented 4-block inclusive PCI range detection for Nvidia Kepler/Fermi to prevent black screens.
- Centralized system time verification checking against year 2026 before APT execution.
- Cleaned and purged modern package lists for the Bullseye extra software module.
- Updated main menu with conditional sourcing and fixed Option 7 (Gaming Lite) for Bullseye.
- Updated README.md with explicit TUI navigation instructions and full repository directory tree mapping.

modules/bullseye/repos.sh

@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+# repos.sh — Bullseye: repos clásicos con archive phase
+# License GPL v3
+
+configure_repos_bullseye() {
+    echo -e "${YELLOW}Repository configuration — Debian 11 Bullseye${NC}"
+
+    local info="Configuración de repositorios para Debian 11 Bullseye.\n\n"
+    info+="Se usarán los repositorios oficiales con componentes\n"
+    info+="main, contrib y non-free (sin non-free-firmware).\n"
+    info+="No se utiliza formato DEB822.\n"
+    if $BULLSEYE_USE_ARCHIVE; then
+        info+="\nModo Archive: Las URLs apuntarán a archive.debian.org\n"
+        info+="(Bullseye LTS finalizó el 31 Ago 2026)."
+    fi
+    _msg "Repositorios — Bullseye" "$info" 12 65
+
+    if [ -f /etc/apt/sources.list ]; then
+        if ! _confirm "Repositorios" "Ya existe /etc/apt/sources.list.\n\nSobrescribir con la configuración de Bullseye?"; then
+            echo "Manteniendo configuración actual."
+            return 0
+        fi
+    fi
+
+    local base_uri="https://deb.debian.org/debian"
+    local security_uri="https://security.debian.org/debian-security"
+    if $BULLSEYE_USE_ARCHIVE; then
+        base_uri="https://archive.debian.org/debian"
+        security_uri="https://archive.debian.org/debian-security"
+    fi
+
+    local content=""
+    content="# Oficial Repo\n"
+    content+="deb ${base_uri} bullseye main contrib non-free\n"
+    content+="#deb-src ${base_uri} bullseye main contrib non-free\n\n"
+
+    content+="# Updates\n"
+    content+="deb ${base_uri} bullseye-updates main contrib non-free\n"
+    content+="#deb-src ${base_uri} bullseye-updates main contrib non-free\n\n"
+
+    content+="# Security\n"
+    content+="deb ${security_uri} bullseye-security main contrib non-free\n"
+    content+="#deb-src ${security_uri} bullseye-security main contrib non-free\n"
+
+    echo -e "$content" | sudo tee /etc/apt/sources.list > /dev/null
+
+    echo "Actualizando listas de paquetes..."
+    if sudo apt update; then
+        echo -e "${GREEN}Repositorios de Debian 11 Bullseye configurados.${NC}"
+    else
+        echo -e "${RED}apt update falló. Revise su conexión de red.${NC}"
+        return 1
+    fi
+}