system overhaul and bug fixeds

- Replaced the fragile upstream script installer with native Deb822 repository injection and automated GPG keyring management in `jellyfin.sh`. Eliminated external dependencies, checksums, and interactive flags for guaranteed non-interactive support across Bullseye/Bookworm/Trixie.
- Upgraded the NVMe module (`modules/extras/system/system.sh`) to perform multi-drive scanning with dynamic `lsblk` parsing. Replaced single-disk detection logic with a `while read` loop to capture all devices, displaying formatted SMART health diagnostics (Critical Warning, Temperature, Percentage Used).
- Overhauled the 'System Information' TUI into a multi-device dashboard featuring standalone GPU/Driver hierarchies and dynamic storage mapping. Added new globals (`DISPLAY_SERVER`, `STORAGE_SUMMARY`) and comprehensive arrays for Network/Wi-Fi interface indexing in `modules/utils.sh`.
- Redesigned the graphics stack layout to fix multi-GPU text clipping and unified Mesa version prompting logic. Integrated post-install package telemetry to display live versions in the completion screen, separating planning visualization from installation decision points in `modules/gpu.sh`.
- Fixed non-free-firmware conceptual documentation bugs and expanded Backports descriptions with hardware-focused educational text. Added non-free repository safeguards for Trixie/Bullseye compatibility under "Firmware & Wireless Drivers".
- Refactored repository logic in modules/repos.sh to eliminate dead code (redundant default_text variables) and strict-hardcoded layout behaviors, standardizing dialog geometry to a clean matrix.
- Updated README.md

modules/bullseye/extras.sh

@@ -24,6 +24,14 @@ _quick_install_bullseye() {
 install_firmware_bullseye() {
     echo -e "${YELLOW}Installing firmware-linux-nonfree (Bullseye)...${NC}"
 
+    # ── Safeguard: non-free repos must be enabled ──
+    if ! grep -qr "non-free" /etc/apt/sources.list /etc/apt/sources.list.d/ 2>/dev/null; then
+        _msg "Error" "Error: No 'non-free' repositories were detected.\n\
+Please first run the 'Configure repositories' option in the\n\
+main menu to install proprietary firmwares." 10 65
+        return 1
+    fi
+
     if is_installed "firmware-linux-nonfree"; then
         echo "firmware-linux-nonfree already installed."
         return