Add converge-wake.service and systemd-sleep hook for wake-from-sleep sync

Creates a oneshot user service (converge-wake.service) that runs
converge --sync after the network is online, and a systemd-sleep hook
(/usr/lib/systemd/system-sleep/converge-wake) that triggers the service
for each logged-in user on resume.

Uses After=network-online.target for proper network timing on
NetworkManager/systemd-networkd setups, with a 5-second ExecStartPre
delay as a safety net for netctl and other environments where
network-online.target may not gate on resume.

Updated PKGBUILD and AGENTS.md accordingly.

PKGBUILD

@@ -15,11 +15,15 @@ optdepends=('converge-relay: realtime push notifications via SSE relay server')
 backup=('etc/converge/config.example.yaml')
 source=(
     "converge.service"
+    "converge-wake.service"
     "converge.example.yaml"
+    "src/system-sleep/converge-wake"
 )
 md5sums=(
     'SKIP'
     'SKIP'
+    'SKIP'
+    'SKIP'
 )
 
 build() {
@@ -54,9 +58,15 @@ package() {
     install -Dm755 "$srcdir/bin/converge" \
         "$pkgdir/usr/bin/converge"
 
-    # User systemd service
+    # User systemd services
     install -Dm644 converge.service \
         "$pkgdir/usr/lib/systemd/user/converge.service"
+    install -Dm644 converge-wake.service \
+        "$pkgdir/usr/lib/systemd/user/converge-wake.service"
+
+    # Sleep hook (runs converge --sync for all logged-in users after resume)
+    install -Dm755 src/system-sleep/converge-wake \
+        "$pkgdir/usr/lib/systemd/system-sleep/converge-wake"
 
     # Example config
     install -Dm644 converge.example.yaml \