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

README.md

@@ -85,27 +85,51 @@ Queries Podman and Docker for running containers, adds new ones to the config, a
 sudo unitdore edit
 ```
 
-Opens `/etc/unitdore/units.yaml` in `$EDITOR` (falls back to `vi`).
+Opens `/etc/unitdore/units.yaml` in `$EDITOR` (falls back to `nvim`, `nano`, `vi`; creates the config dir if missing).
 
-### Install systemd unit files
+### Install service files
 
 ```bash
-sudo unitdore install
+sudo unitdore install <name>
 ```
 
-Generates `.service` files for all enabled units and writes them to systemd. Use `--dry-run` to preview without writing.
+Generates the service file for one enabled unit (error if unknown or disabled). Does not enable or start it.
 
 ```bash
-sudo unitdore install --dry-run
+sudo unitdore install <name> --dry-run   # preview, write nothing
+sudo unitdore install --all              # all enabled units; installed + disabled ones are stopped and removed
+sudo unitdore installall                 # same as install --all
 ```
 
-### Enable and start units
+### Start / stop / enable / uninstall
 
 ```bash
-sudo unitdore active
+sudo unitdore start <name>       # start only
+sudo unitdore enable <name>      # enable at boot + start
+sudo unitdore stop <name>
+sudo unitdore uninstall <name>   # stop, disable, remove service file
 ```
 
-Runs `systemctl enable --now` for all installed, enabled units in startup order.
+Each takes `--all` instead of a name to act on every unit (shortcuts: `startall`, `enableall`, `stopall`, `uninstallall`, `installall`).
+
+- `start/enable --all`: installed, enabled units in `order` (lowest first); same `order` → parallel
+- `stop/uninstall --all`: all installed units, reverse `order`, one at a time
+
+### Order and delay at boot
+
+`order`/`delay` are written into the generated service files, so they also apply at boot.
+
+| Backend | `order` | `delay` |
+|---|---|---|
+| systemd | `After=` units of the previous group | `ExecStartPre=sleep N`, `TimeoutStartSec=N+90` |
+| OpenRC | `depend() { after … }` | `start_pre() { sleep N }` |
+| runit | `sv -w 30 check <prev>` in `run` | `sleep N` in `run` |
+
+- Previous group = nearest lower `order` among enabled units of the same user
+- `delay` is the unit's own, ignored in the first group
+- Changing `order`/`enabled` via `update` regenerates all installed, enabled units
+- Delay also applies to manual `start` and to restarts
+- `delay` must be a valid non-negative duration (`5s`, `1m`); an invalid value fails config load
 
 ### Check status
 
@@ -139,7 +163,7 @@ units:
     user: ""                 # empty = root/system unit
     command: ""              # optional: override ExecStart entirely
     order: 1                 # startup order (lower = earlier)
-    delay: 0s                # delay after previous order group
+    delay: 0s                # wait before start (own delay, not first group)
     enabled: true
     disabled_reason: ""      # auto-set by syncup reconciliation