feat: harden dashcam transfer tegen flakke SD-lezer + stale-mount cleanup

- dashcam-transfer.py: log echte OSError (shutil.copy2 i.p.v. cp), pre-flight
  leesbaarheidscheck voor ruimte-wissen, retry (3x) + early-abort (5x), guards
  op bestandssysteem-calls, WhatsApp GESTOPT bij defecte kaart
- dashcam-transfer-mount.sh: skip als service al draait, read-only fsck.exfat
  health check, %k device-naam doorgeven
- dashcam-transfer-cleanup.sh: nieuw - ruimt stale mount op bij udev REMOVE
- udev/99-dashcam-trigger.rules: ADD + REMOVE regels met %k
- tests: 20 python + 7 mount + 12 cleanup checks
- README: architectuur, robuustheid, deploy-instructies

dashcam-transfer-mount.sh

@@ -1,15 +1,22 @@
 #!/bin/bash
-# Mount SD card and start dashcam transfer.
+# Mount SD card by kernel device name (udev %k) and start dashcam transfer.
 # Called by udev rule 99-dashcam-trigger.rules via systemd-run.
 # systemd-run is used (not direct udev exec) because udev context
 # lacks mount/umount permissions on Fedora with SELinux enforcing.
-#
-# The udev rule passes the kernel name (e.g. "sde1") as $1 so the
-# device is mounted dynamically, independent of its filesystem UUID.
+MAX_WAIT="${DASHCAM_MAX_WAIT:-60}"
+
 DEV=${1:+/dev/$1}
 logger -t dashcam-transfer "Trigger: SD card detected ($DEV)"
+
+# Never interrupt a running transfer: a flaky reader can cause a second
+# udev event (USB re-enumeration) which must not unmount a busy card.
+if systemctl is-active --quiet dashcam-transfer.service; then
+    logger -t dashcam-transfer "Trigger: transfer service al bezig — skip"
+    exit 0
+fi
+
 if [ -n "$1" ]; then
-    for ((i=0; i<60; i++)); do
+    for ((i=0; i<MAX_WAIT; i++)); do
         if [ -e "$DEV" ]; then
             logger -t dashcam-transfer "Trigger: device ready after ${i}s"
             break
@@ -19,7 +26,7 @@ if [ -n "$1" ]; then
 else
     UUID=$(lsblk -rno UUID /dev/sde1 2>/dev/null)
     DEV=/dev/disk/by-uuid/$UUID
-    for ((i=0; i<60; i++)); do
+    for ((i=0; i<MAX_WAIT; i++)); do
         if [ -e "$DEV" ]; then
             logger -t dashcam-transfer "Trigger: device ready after ${i}s"
             break
@@ -27,13 +34,20 @@ else
         sleep 1
     done
 fi
+
 while mountpoint -q /mnt/sdcard 2>/dev/null; do
     umount /mnt/sdcard 2>/dev/null || break
 done
+
 mount "$DEV" /mnt/sdcard -o uid=1000,gid=1000,fmask=0000,dmask=0000
 if [ $? -eq 0 ]; then
     logger -t dashcam-transfer "Trigger: mounted, starting transfer"
+    # Read-only exFAT health check; logs warnings but never blocks the transfer.
+    if command -v fsck.exfat >/dev/null 2>&1; then
+        fsck.exfat -n "$DEV" 2>&1 | logger -t dashcam-transfer
+        logger -t dashcam-transfer "Trigger: fsck.exfat exit ${PIPESTATUS[0]}"
+    fi
     systemctl start dashcam-transfer
 else
     logger -t dashcam-transfer "TRIGGER ERROR: mount failed"
-fi
+fi