add retroarch, nvidia - java - internet refactor

- NVIDIA CUDA extrepo refactor in `modules/gpu/nvidia.sh`: removed unnecessary `i386_active` lines, updated warning to reference `v590 (unified metapackage)`, simplified installation from 18+10 versioned packages → `nvidia-driver-pinning-590 nvidia-driver firmware-nvidia-gsp`, eliminated `apt-mark hold` since pinning packages now handle it. DKMS verification and `NVIDIA_DRIVER_MODE="cuda-repo"` preserved.
- CUDA repo case fix in `modules/gaming.sh`: replaced silent bypass with detection of `nvidia-driver-libs:i386` v590 installation; if missing, prompts user confirmation before installing via active CUDA repo + pinning.
- Palemoon internet module overhaul (`modules/extras/internet/internet.sh`): removed deprecated `_enable_palemoon_repo()`, created new `install_palemoon()` with AVX2→AVX→SSE2 CPU detection from `/proc/cpuinfo`, proper `extrepo enable` call, and package installation.
- ProtonVPN module rewrite (`modules/extras/internet/internet.sh`): removed broken `_enable_protonvpn_repo()` that failed due to missing suite; created new `install_protonvpn()` using `stable` suite + `proton-vpn-gtk-app` package with proper validation.
- Java/Minecraft rename across `modules/gaming.sh` and `modules/extras/java.sh`: renamed `_install_gaming_java()` → `install_minecraft_java()`, updated menu title from "Java Runtimes for Gaming" to "Java Runtimes for Minecraft", changed whiptail tag from `"java-jre"` to `"java"`.
- RetroArch + 4 classic cores (`modules/gaming/tools.sh` and `.sh`): added RetroArch entry to gaming menu, new case handler in `gaming.sh`, updated installation command to include `libretro-mgba libretro-snes9x libretro-nestopia libretro-gambatte`, enhanced notice with emojis, core enumeration, DFSG warning, and wiki link.
- OnlyOffice server status (`modules/extras/office/office.sh`): added fallback message for slow or down OnlyOffice servers to improve user experience during installation.
- Full syntax validation: all modified files pass `bash -n` without errors; no residual references to old variables (`i386_active`, `590.48.01`) or functions remain.
- Documentation about Debian and the script is added to supplement important information.
- update README.md

modules/gaming/tools.sh

@@ -61,3 +61,30 @@ install_openrgb() {
     rm -f "${deb_path}"
     echo -e "${GREEN}OpenRGB installed. NOTE: You must reboot or log out/in for the 'i2c' group to take effect.${NC}"
 }
+
+install_retroarch() {
+    if is_installed "retroarch"; then
+        echo "RetroArch already installed."
+        return
+    fi
+
+    _run_cmd "RetroArch" "sudo apt install -y retroarch libretro-mgba libretro-snes9x libretro-nestopia libretro-gambatte" "Installing RetroArch and classic cores (GBA, SNES, NES, GB)..."
+
+    clear
+    echo "================================================================="
+    echo "  🎮  IMPORTANT RETROARCH NOTICE  🎮"
+    echo "================================================================="
+    echo "Good news! Nintendo (NES/SNES) and Game Boy (GB/GBA) cores"
+    echo "have been automatically installed and are ready to play!"
+    echo ""
+    echo "⚠️ However, due to Debian open-source guidelines:"
+    echo "   - Core auto-updates inside the app are disabled."
+    echo "   - Heavy/arcade cores or those requiring proprietary BIOS"
+    echo "     (like PlayStation or Arcade) must be handled manually."
+    echo ""
+    echo "👉 To learn how to unlock the internal Online Downloader:"
+    echo "   Please check our repository's documentation or visit:"
+    echo "   https://wiki.debian.org/RetroArch"
+    echo "================================================================="
+    read -p "Press ENTER to continue..."
+}