Add one-command server mod updates: build_mods.py --push via update.sh (stop/sync/start, prunes stale jars)

server/README.md

@@ -22,7 +22,7 @@ and verifies every mod by sha1 before installing.
 |------|--------|
 | System packages | `openjdk-21-jre-headless`, `curl`, `unzip` (needs root/`sudo`) |
 | NeoForge server | Official installer from Maven → server files + `libraries/` |
-| Mods | Downloads the 90 server-safe mods pinned in `mods.json`, sha1-verified |
+| Mods | Downloads the 90 server-safe mods pinned in `mods.json`, sha1-verified; prunes jars no longer in the pack |
 | Config | `eula.txt` (EULA accepted), `server.properties` (IP, motd, 8 G) |
 | Run script | `run.sh` with 8 GB + G1GC (`nogui`) |
 
@@ -54,13 +54,57 @@ Stop the server cleanly with the console command `stop` (Ctrl-c also works).
   the server will crash with `Cannot assign requested address`.
 - `difficulty=hard`, `spawn-protection=0`, `view-distance=10` are set for the
   airship-focused, land-claim-friendly experience.
-- The 19 client-only mods (Iris/shaders, Sodium, Minimap, Jade, JEI, etc.) are
-  intentionally excluded here — the server is pure gameplay logic.
+- The 17 client-only mods (Iris/shaders, Sodium, Minimap, MouseTweaks, etc.)
+  are intentionally excluded here — everything gameplay-relevant runs on the
+  server too (including JEI and Jade).
 
-## Updating the pack
+## Updating the server's mods
 
-1. Add/remove mods in the Prism instance `Reaper's Sky - dev`.
-2. Rebuild + push the mrpack (see repo root `README.md`).
-3. Re-run `server/build_mods.py` or regenerate `mods.json`, commit, push.
-4. On the server: `git pull && sudo ./deploy.sh && ./run.sh`
-   (also remove any stale jars from `~/reaper-sky-server/mods/` first).
+### The easy way — one command from your PC
+
+If your PC has SSH key access to the server (`ssh root@ReapersSky` works
+without a password), you can push mod changes to the live server with a single
+command run **from the repo root on your PC**:
+
+```sh
+python3 server/build_mods.py --push
+```
+
+This does everything:
+
+1. Scans the Prism instance `Reaper's Sky - dev` and regenerates
+   `server/mods.json` (skipping client-only mods).
+2. Uploads that manifest to the server.
+3. On the server: **stops** it cleanly, **syncs** `mods/` against the manifest
+   (deletes jars that are no longer in the pack, downloads + sha1-verifies new
+   or changed ones), then **starts** it again.
+4. Waits for boot and prints `Server is UP` once the log shows `Done (...)`.
+
+No git commit/push is needed first — it works straight from your working tree,
+so you can test changes on the server before committing them.
+
+Useful variations:
+
+```sh
+python3 server/build_mods.py --push          # full cycle: stop -> sync -> start
+RS_SERVER_HOST=user@otherhost python3 server/build_mods.py --push   # different box
+```
+
+### Manual / on-server way
+
+If you already have a `mods.json` on the server (e.g. uploaded by hand), run
+this **on the server box**:
+
+```sh
+bash ~/update.sh /path/to/mods.json        # stop -> sync -> start
+bash ~/update.sh /path/to/mods.json --no-start   # sync only, leave stopped
+```
+
+`update.sh` is safe to re-run at any time: if the server isn't running it just
+syncs; every jar is verified by sha1 before it counts as installed.
+
+### Full reinstall
+
+For a brand-new box (or to rebuild everything from scratch), use the one-shot
+installer described at the top — it also prunes stale jars since it shares the
+same sync logic.