Make the schema files match the server (closes #218)

Each file in schema/ now describes what the HTTP API on next sends and
accepts. A numeric reply has its name in command and its number in code.
body is always an array of strings. MODE, KICK and JOIN carry their
values in body, and TOPIC needs a non-empty body. PING takes no token,
and its PONG is the HTTP response. A channel name is limited to 63
characters, and the leading # is optional from a client.

PUBKEY.json is deleted, since the server has no such command. The
section of schema/README.md that listed the differences is removed,
and the sentences it made false are corrected.

Model: opus-5-5

schema/numerics/002.json

@@ -2,34 +2,48 @@
   "$schema": "https://json-schema.org/draft/2020-12/schema",
   "$id": "https://sneak.berlin/go/neoirc/schema/numerics/002.json",
   "title": "002 RPL_YOURHOST",
-  "description": "Server host info sent after session creation. RFC 2812 \u00a75.1.",
+  "description": "The server's name and version. Sent right after RPL_WELCOME. RFC 2812 §5.1.",
   "$ref": "../message.json",
   "properties": {
     "command": {
-      "const": "002"
+      "const": "RPL_YOURHOST"
+    },
+    "code": {
+      "const": 2
+    },
+    "from": {
+      "type": "string",
+      "description": "The server name."
     },
     "to": {
-      "type": "string"
+      "type": "string",
+      "description": "The user's nick."
     },
     "body": {
       "type": "array",
       "items": {
         "type": "string"
       },
-      "description": "Host info lines."
+      "description": "One string: 'Your host is ', the server name, ', running version ' and the version.",
+      "minItems": 1,
+      "maxItems": 1
     }
   },
   "required": [
     "command",
+    "code",
+    "from",
     "to",
     "body"
   ],
   "examples": [
     {
-      "command": "002",
+      "command": "RPL_YOURHOST",
+      "code": 2,
+      "from": "neoirc",
       "to": "alice",
       "body": [
-        "Your host is neoirc.example.com, running version 0.1.0"
+        "Your host is neoirc, running version dev"
       ]
     }
   ]