Integrity fixes: atomic writes, rc checks, curl

- Verified the repository backup rc in migrate.sh. `_persistent_backup_repos()` now aborts before any destructive step when the tar archive is missing or corrupt, removing the invalid backup itself.
- Verified the restore rc in migrate.sh. `_restore_backup()` now reports failure instead of printing a green "Backup restored" message, and its caller distinguishes a restored backup from a failed restore.
- Made the upgrade phases fail honestly. `apt upgrade` and `apt full-upgrade` now abort with `apt --fix-broken install` + `dpkg --configure -a` instructions instead of reporting "completed successfully" over a partially-upgraded system.
- Made repository source writes atomic. Both writers tee into a `.tmp` file and move into place, and the `/etc/apt/sources.list` removal now happens after the write.
- Corrected the SID warning text in migrate.sh to reflect that security fixes arrive via package uploads rather than a nonexistent sid-security suite.
- Added exit-path cleanup traps for the temp `.deb` files: `trap 'rm -f "$deb_path"' RETURN` in `heroic.sh`and `tools.sh`.
- Tightened Heroic download handling: the API fetch uses `curl -fsS --connect-timeout 10 --max-time 30`, the download uses `curl -fsSL --max-time 300`, and the `.deb` is validated with both `dpkg-deb --info` and `dpkg-deb --contents`; `sudo apt install` is guarded with `if !` before the temporary file is deleted.
- Tightened the OpenRGB install path: the Codeberg API fetch uses `curl -fsS --connect-timeout 10 --max-time 30` and the download `curl -fsSL --max-time 300`, with the same dual `dpkg-deb` integrity check as the Heroic fallback.
- Guarded the OpenRGB post-install side effects: the script now aborts after removing the failed `.deb` if `sudo apt install` returns non-zero, so `modprobe i2c-dev`, `/etc/modules`, the `i2c` group membership, `udevadm`, and the `setcap` step no longer run when the package is absent.

modules/desktop_display.sh

@@ -1,6 +1,10 @@
 #!/usr/bin/env bash
 
 manage_desktop_display() {
+    # Hardware state is detected on demand; HAS_NVIDIA
+    # (GDM3 Wayland option) is populated by the battery.
+    _ensure_state_detected
+
     while true; do
         local choice
         choice=$(_menu "Desktop & Display" \