Add embedded web chat client (closes #7) (#8)

schema/numerics/433.json

@@ -0,0 +1,47 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://git.eeqj.de/sneak/chat/schema/numerics/433.json",
+  "title": "433 ERR_NICKNAMEINUSE",
+  "description": "Nickname is already in use. RFC 1459 \u00a76.1.",
+  "$ref": "../message.json",
+  "properties": {
+    "command": {
+      "const": "433"
+    },
+    "to": {
+      "type": "string"
+    },
+    "params": {
+      "type": "array",
+      "items": {
+        "type": "string"
+      },
+      "description": "[requested_nick]."
+    },
+    "body": {
+      "type": "array",
+      "items": {
+        "type": "string"
+      },
+      "description": "Nickname is already in use",
+      "maxItems": 1
+    }
+  },
+  "required": [
+    "command",
+    "to",
+    "params"
+  ],
+  "examples": [
+    {
+      "command": "433",
+      "to": "*",
+      "params": [
+        "alice"
+      ],
+      "body": [
+        "Nickname is already in use"
+      ]
+    }
+  ]
+}