fix(packaging): address code review findings

- Upgrade path restarts only fenris-collect.timer, not fenris-collect.service
  (spec §7: "a running oneshot finishes on its old interpreter")
- Remove redundant deb depends override in nfpm.yaml (top-level is sufficient)
- Remove common.sh sourcing — scripts are self-contained to avoid path
  dependency when dpkg/rpm run them from /var/lib/dpkg/info/

Co-authored-by: CommandCodeBot <noreply@commandcode.ai>

packaging/rpm/post.sh

@@ -1,8 +1,5 @@
 #!/bin/sh
 # RPM %post — post-install/upgrade scriptlet (spec §7).
-#
-# Fresh install: sysusers, tmpfiles, daemon-reload — nothing else (dormant).
-# Upgrade: snapshot, migration, daemon-reload, conditional timer restart.
 set -eu
 
 STORE_DIR="/var/lib/fenris"
@@ -16,11 +13,10 @@ if [ "$1" -eq 1 ]; then
     systemd-tmpfiles --create  || true
     systemctl daemon-reload  || true
 elif [ "$1" -ge 2 ]; then
-    # Upgrade
+    # Upgrade — snapshot, migration, daemon-reload, conditional timer restart
     if [ -f "${STORE_DB}" ]; then
         cp "${STORE_DB}" "${STORE_BAK}" 2>/dev/null || true
     fi
-
     if [ -x "${VENV_PYTHON}" ] && [ -f "${STORE_DB}" ]; then
         "${VENV_PYTHON}" -c "
 from fenris.store import migrate_to_latest
@@ -29,12 +25,8 @@ n = migrate_to_latest(Path('${STORE_DB}'))
 print(f'Fenris migration: {n} step(s) applied') if n else None
 " 2>&1 || echo "Fenris: migration skipped (store not yet initialized)"
     fi
-
-    systemd-sysusers  || true
-    systemd-tmpfiles --create  || true
-    systemctl daemon-reload  || true
-
-    for unit in fenris-collect.timer fenris-collect.service; do
+    systemctl daemon-reload 2>/dev/null || true
+    for unit in fenris-collect.timer; do
         if systemctl is-active --quiet "${unit}" 2>/dev/null; then
             TMPFILE="$(mktemp)"
             systemctl cat "${unit}" > "${TMPFILE}" 2>/dev/null || true