feat: order/delay in service files, enable cmd, --all on unit commands

- install/uninstall/start/stop/enable take <name> or --all; *all kept as shortcuts
- add enable (enable at boot + start); startall no longer enables
- order/delay resolved by config.ResolveOrder and written into systemd,
  OpenRC and runit service files (After=/sleep), so they apply at boot
- install --all stops and disables units before removing their files
- update regenerates all installed, enabled units and removes disabled ones
- edit creates the config dir; docs and man page updated
- tests: fake Init for cmd, ResolveOrder, backend ordering output

docs/unitdore.1

@@ -30,29 +30,38 @@ podman\-compose containers become one \fBkind: stack\fR unit per project;
 existing member units are disabled. As root, rootless Podman containers of
 each user in \fBusers:\fR are also discovered.
 .TP
-.B install
-Generate \fI.service\fR files for all enabled units and write them to the
-appropriate systemd directory. Use \fB\-\-dry\-run\fR to preview without writing.
+.B install \fIname\fR | \fB\-\-all\fR
+Generate the service file for one enabled unit. Does not enable or start it.
+Use \fB\-\-dry\-run\fR to preview without writing. With \fB\-\-all\fR (and no
+name) it behaves like \fBinstallall\fR.
 .TP
-.B uninstall \fIname\fR
-Disable, stop, and remove the service file for a specific unit.
+.B installall
+Generate service files for all enabled units. Disabled units that are
+installed are stopped, disabled and removed. Supports \fB\-\-dry\-run\fR.
 .TP
-.B startall
-Run \fBsystemctl enable \-\-now\fR for all enabled, installed units in startup
-order.
+.B uninstall \fIname\fR | \fB\-\-all\fR
+Disable, stop, and remove the service file for a unit. With \fB\-\-all\fR, for
+every installed unit in reverse startup order (same as \fBuninstallall\fR).
 .TP
-.B stopall
-Run \fBsystemctl disable \-\-now\fR for all installed units in reverse startup
-order.
+.B start \fIname\fR | \fB\-\-all\fR
+Start an installed unit without enabling it at boot. With \fB\-\-all\fR, start
+all enabled, installed units in startup order: equal \fBorder\fR in parallel,
+groups one after another (same as \fBstartall\fR). \fBorder\fR and \fBdelay\fR are
+also written into the service files (systemd \fBAfter=\fR and \fBExecStartPre\fR,
+OpenRC \fBafter\fR and \fBstart_pre\fR, runit \fBsv check\fR and \fBsleep\fR), so
+they apply at boot.
 .TP
-.B start \fIname\fR
-Start a specific unit by name (\fBsystemctl start\fR).
+.B enable \fIname\fR | \fB\-\-all\fR
+Like \fBstart\fR, but also enable at boot (same as \fBenableall\fR).
 .TP
-.B stop \fIname\fR
-Stop a specific unit by name (\fBsystemctl stop\fR).
+.B stop \fIname\fR | \fB\-\-all\fR
+Stop an installed unit. With \fB\-\-all\fR, stop all installed units one at a time
+in reverse startup order (same as \fBstopall\fR).
 .TP
 .B update \fIname\fR
-Update a unit's config and recreate its service file.
+Update a unit's config. An installed unit's service file is recreated, or
+stopped and removed if the unit is now disabled. Other installed units are
+regenerated too, as ordering depends on their neighbours.
 .RS
 .TP
 .BR \-\-order " " \fIn\fR
@@ -127,15 +136,15 @@ Discover containers and install their service files:
 .RS
 .nf
 sudo unitdore syncup
-sudo unitdore install
-sudo unitdore startall
+sudo unitdore install \-\-all
+sudo unitdore start \-\-all
 .fi
 .RE
 .PP
 Preview generated service files without writing:
 .PP
 .RS
-sudo unitdore install \-\-dry\-run
+sudo unitdore install nginx \-\-dry\-run
 .RE
 .PP
 Start a single container unit: