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/003.json

@@ -2,31 +2,45 @@
   "$schema": "https://json-schema.org/draft/2020-12/schema",
   "$id": "https://sneak.berlin/go/neoirc/schema/numerics/003.json",
   "title": "003 RPL_CREATED",
-  "description": "Server creation date. RFC 2812 \u00a75.1.",
+  "description": "The date the server last started. Sent right after RPL_YOURHOST. RFC 2812 §5.1.",
   "$ref": "../message.json",
   "properties": {
     "command": {
-      "const": "003"
+      "const": "RPL_CREATED"
+    },
+    "code": {
+      "const": 3
+    },
+    "from": {
+      "type": "string",
+      "description": "The server name."
     },
     "to": {
-      "type": "string"
+      "type": "string",
+      "description": "The user's nick."
     },
     "body": {
       "type": "array",
       "items": {
         "type": "string"
       },
-      "description": "Text lines."
+      "description": "One string: 'This server was created ' and the start date as YYYY-MM-DD.",
+      "minItems": 1,
+      "maxItems": 1
     }
   },
   "required": [
     "command",
+    "code",
+    "from",
     "to",
     "body"
   ],
   "examples": [
     {
-      "command": "003",
+      "command": "RPL_CREATED",
+      "code": 3,
+      "from": "neoirc",
       "to": "alice",
       "body": [
         "This server was created 2026-02-01"