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

tests/test_mount_script.sh

@@ -0,0 +1,98 @@
+#!/bin/bash
+# Functional test for dashcam-transfer-mount.sh using fake tools on PATH.
+set -u
+
+SCRIPT="$(cd "$(dirname "$0")/.." && pwd)/dashcam-transfer-mount.sh"
+WORK=$(mktemp -d)
+trap 'rm -rf "$WORK"' EXIT
+
+FAKEBIN="$WORK/bin"
+mkdir -p "$FAKEBIN"
+
+LOGGER_FILE="$WORK/logger.log"
+MOUNT_LOG="$WORK/mount.log"
+FSCK_LOG="$WORK/fsck.log"
+MOUNT_MARKER="$WORK/mounted"
+START_MARKER="$WORK/started"
+
+export LOGGER_FILE MOUNT_LOG FSCK_LOG MOUNT_MARKER START_MARKER
+
+cat > "$FAKEBIN/logger" <<'EOF'
+#!/bin/bash
+echo "logger: $*" >> "$LOGGER_FILE"
+EOF
+
+cat > "$FAKEBIN/systemctl" <<'EOF'
+#!/bin/bash
+if [ "$1" = "is-active" ]; then
+    case "$2" in
+        --quiet) ;;
+        *) echo "$SYSTEMCTL_STATE" ;;
+    esac
+    [ "$SYSTEMCTL_STATE" = "active" ]
+elif [ "$1" = "start" ]; then
+    touch "$START_MARKER"
+fi
+EOF
+
+cat > "$FAKEBIN/mount" <<'EOF'
+#!/bin/bash
+echo "mount $*" >> "$MOUNT_LOG"
+touch "$MOUNT_MARKER"
+exit 0
+EOF
+
+cat > "$FAKEBIN/umount" <<'EOF'
+#!/bin/bash
+exit 0
+EOF
+
+cat > "$FAKEBIN/mountpoint" <<'EOF'
+#!/bin/bash
+exit 1
+EOF
+
+cat > "$FAKEBIN/fsck.exfat" <<'EOF'
+#!/bin/bash
+echo "fsck $*" >> "$FSCK_LOG"
+exit 0
+EOF
+
+cat > "$FAKEBIN/lsblk" <<'EOF'
+#!/bin/bash
+exit 0
+EOF
+
+chmod +x "$FAKEBIN"/*
+
+pass=0
+fail=0
+check() { # $1=desc, $2=condition
+    if eval "$2"; then
+        echo "PASS: $1"
+        pass=$((pass + 1))
+    else
+        echo "FAIL: $1"
+        fail=$((fail + 1))
+    fi
+}
+
+# Test 1: service already active → skip, never unmount/mount/start
+export SYSTEMCTL_STATE=active
+rm -f "$MOUNT_MARKER" "$START_MARKER" "$LOGGER_FILE" "$MOUNT_LOG" "$FSCK_LOG"
+PATH="$FAKEBIN:$PATH" DASHCAM_MAX_WAIT=0 "$SCRIPT" sde1
+check "service actief → exit zonder mount" 'test ! -e "$MOUNT_MARKER"'
+check "service actief → geen service start" 'test ! -e "$START_MARKER"'
+check "service actief → skip gelogd" 'grep -q "al bezig" "$LOGGER_FILE"'
+
+# Test 2: service inactive → mount, fsck, start
+export SYSTEMCTL_STATE=inactive
+rm -f "$MOUNT_MARKER" "$START_MARKER" "$LOGGER_FILE" "$MOUNT_LOG" "$FSCK_LOG"
+PATH="$FAKEBIN:$PATH" DASHCAM_MAX_WAIT=0 "$SCRIPT" sde1
+check "service inactief → gemount" 'test -e "$MOUNT_MARKER"'
+check "service inactief → service gestart" 'test -e "$START_MARKER"'
+check "fsck.exfat uitgevoerd" 'test -s "$FSCK_LOG"'
+check "mount gelogd" 'grep -q "mounted, starting transfer" "$LOGGER_FILE"'
+
+echo "=== $pass pass, $fail fail ==="
+[ "$fail" -eq 0 ]