feat(etna): migrate shlink to camasca package and postgres

Flake lock file updates:

• Updated input 'camasca':
    'git+https://git.uku3lig.net/uku/camasca?ref=refs/heads/main&rev=70b5e931bacc4a59cdef5b5ea26d3f968c52b332' (2025-01-24)
  → 'git+https://git.uku3lig.net/uku/camasca?ref=refs/heads/main&rev=edcd0a4ddf59dc9cbacf539e019da0c65896be5e' (2025-01-29)

flake.lock

@@ -57,11 +57,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1737728406,
-        "narHash": "sha256-m0Fn7+PJHKaARelpu39oe1THO2CbGTpDTj9W4rtXAJs=",
+        "lastModified": 1738146869,
+        "narHash": "sha256-AzAz5+EgiF9CTXspgIHCna4XwA4RvQJq2bldGI/G8Cg=",
         "ref": "refs/heads/main",
-        "rev": "70b5e931bacc4a59cdef5b5ea26d3f968c52b332",
-        "revCount": 44,
+        "rev": "edcd0a4ddf59dc9cbacf539e019da0c65896be5e",
+        "revCount": 50,
         "type": "git",
         "url": "https://git.uku3lig.net/uku/camasca"
       },

systems/etna/shlink.nix

@@ -1,13 +1,29 @@
+{ camasca, ... }:
 {
+  imports = [ camasca.nixosModules.shlink ];
+
   cfTunnels."uku.moe" = "http://localhost:8081";
 
-  virtualisation.oci-containers.containers.shlink = {
-    image = "shlinkio/shlink:stable";
-    ports = [ "8081:8080" ];
-    volumes = [ "/data/shlink/database.sqlite:/etc/shlink/data/database.sqlite" ];
+  services = {
+    shlink = {
+      enable = true;
       environment = {
+        PORT = "8081";
         DEFAULT_DOMAIN = "uku.moe";
         IS_HTTPS_ENABLED = "true";
+        DB_DRIVER = "postgres";
+        DB_UNIX_SOCKET = "/var/run/postgresql";
+      };
+    };
+
+    postgresql = {
+      ensureDatabases = [ "shlink" ];
+      ensureUsers = [
+        {
+          name = "shlink";
+          ensureDBOwnership = true;
+        }
+      ];
     };
   };
 }