doc: sunken-ship WiFi configuration guide 📝

docs/sunken-ship-wifi.md

@@ -0,0 +1,58 @@
+# Sunken-ship WiFi
+
+WiFi is enabled via [networking.wireless](../nixos/hosts/sunken-ship.nix) with **no networks** in Nix. The NixOS service uses **`/etc/wpa_supplicant/imperative.conf`** (not `/etc/wpa_supplicant.conf`). SSID and PSK stay out of the repo.
+
+## Create the config on the server
+
+The daemon reads **`/etc/wpa_supplicant/imperative.conf`**. Put only the `network={}` block there — do **not** add `ctrl_interface` (the service manages that and will fail if you set it).
+
+**Option A — write directly to imperative.conf:**
+
+```bash
+sudo tee /etc/wpa_supplicant/imperative.conf << 'EOF'
+network={
+    ssid="YOUR_SSID"
+    psk="YOUR_PASSWORD"
+}
+EOF
+sudo chown wpa_supplicant:wpa_supplicant /etc/wpa_supplicant/imperative.conf
+sudo chmod 664 /etc/wpa_supplicant/imperative.conf
+sudo systemctl restart wpa_supplicant
+```
+
+**Option B — use /etc/wpa_supplicant.conf then copy only the network block:**
+
+```bash
+# 1) Create /etc/wpa_supplicant.conf with your network{} block (and optional ctrl_interface lines if you use wpa_cli elsewhere).
+sudo nano /etc/wpa_supplicant.conf   # or tee as above
+
+# 2) Copy only the network block into imperative.conf (strip ctrl_interface so the service doesn't fail).
+sudo sed '/^ctrl_interface/d;/^ctrl_interface_group/d;/^update_config/d' /etc/wpa_supplicant.conf | sudo tee /etc/wpa_supplicant/imperative.conf > /dev/null
+sudo chown wpa_supplicant:wpa_supplicant /etc/wpa_supplicant/imperative.conf
+sudo chmod 664 /etc/wpa_supplicant/imperative.conf
+sudo systemctl restart wpa_supplicant
+```
+
+Or generate the `network{}` block with a hashed PSK (optional):
+
+```bash
+nix shell nixpkgs#wpa_supplicant -c wpa_passphrase "YOUR_SSID" "YOUR_PASSWORD"
+# Use the network={...} part in imperative.conf.
+```
+
+## Rebuild (after changing Nix config)
+
+From the server (flake is in `nixos/`):
+
+```bash
+cd /etc/dotfiles/nixos && sudo nixos-rebuild switch --flake .#sunken-ship
+```
+
+## Verify
+
+- Service: `systemctl status wpa_supplicant`
+- Interface and IP: `ip addr show wlp5s0` — should get an address when associated.
+- Connectivity: `ping -c 2 8.8.8.8` or unplug ethernet and confirm you still have connectivity.
+- Optional (if ctrl_interface is in config):  
+  `nix shell nixpkgs#wpa_supplicant -c wpa_cli -i wlp5s0 status`  
+  Expect `wpa_state=COMPLETED` and your `ssid=` when connected.