docs: add JSON Schema definitions for all message types (draft 2020-12)

C2S (7): send, join, part, nick, topic, mode, ping
S2C (12): message, dm, notice, join, part, quit, nick, topic, mode, system, error, pong
S2S (6): relay, link, unlink, sync, ping, pong

Each message type has its own schema file under schema/{c2s,s2c,s2s}/.
schema/README.md provides an index of all types with descriptions.

schema/c2s/join.json

@@ -0,0 +1,17 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://git.eeqj.de/sneak/chat/schema/c2s/join.json",
+  "title": "C2S Join",
+  "description": "Join a channel. Submitted via POST /api/v1/channels/join.",
+  "type": "object",
+  "properties": {
+    "channel": {
+      "type": "string",
+      "description": "Channel name (# prefix optional, server will add it).",
+      "pattern": "^#?[a-zA-Z0-9_-]+$",
+      "examples": ["#general", "dev"]
+    }
+  },
+  "required": ["channel"],
+  "additionalProperties": false
+}

schema/c2s/mode.json

@@ -0,0 +1,26 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://git.eeqj.de/sneak/chat/schema/c2s/mode.json",
+  "title": "C2S Mode",
+  "description": "Set channel or user mode flags.",
+  "type": "object",
+  "properties": {
+    "channel": {
+      "type": "string",
+      "description": "Target channel.",
+      "pattern": "^#[a-zA-Z0-9_-]+$"
+    },
+    "mode": {
+      "type": "string",
+      "description": "Mode string (e.g. +o, -m, +v).",
+      "pattern": "^[+-][a-zA-Z]+$",
+      "examples": ["+o", "-m", "+v", "+i"]
+    },
+    "target": {
+      "type": "string",
+      "description": "Target nick for user modes (e.g. +o alice). Omit for channel modes."
+    }
+  },
+  "required": ["channel", "mode"],
+  "additionalProperties": false
+}

schema/c2s/nick.json

@@ -0,0 +1,18 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://git.eeqj.de/sneak/chat/schema/c2s/nick.json",
+  "title": "C2S Nick",
+  "description": "Change the user's nickname.",
+  "type": "object",
+  "properties": {
+    "nick": {
+      "type": "string",
+      "description": "Desired new nickname.",
+      "minLength": 1,
+      "maxLength": 32,
+      "pattern": "^[a-zA-Z][a-zA-Z0-9_-]*$"
+    }
+  },
+  "required": ["nick"],
+  "additionalProperties": false
+}

schema/c2s/part.json

@@ -0,0 +1,22 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://git.eeqj.de/sneak/chat/schema/c2s/part.json",
+  "title": "C2S Part",
+  "description": "Leave a channel. Submitted via DELETE /api/v1/channels/{name}.",
+  "type": "object",
+  "properties": {
+    "channel": {
+      "type": "string",
+      "description": "Channel name to leave.",
+      "pattern": "^#[a-zA-Z0-9_-]+$",
+      "examples": ["#general"]
+    },
+    "reason": {
+      "type": "string",
+      "description": "Optional part reason message.",
+      "maxLength": 256
+    }
+  },
+  "required": ["channel"],
+  "additionalProperties": false
+}

schema/c2s/ping.json

@@ -0,0 +1,14 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://git.eeqj.de/sneak/chat/schema/c2s/ping.json",
+  "title": "C2S Ping",
+  "description": "Client keepalive. Server responds with a pong.",
+  "type": "object",
+  "properties": {
+    "token": {
+      "type": "string",
+      "description": "Optional opaque token echoed back in the pong response."
+    }
+  },
+  "additionalProperties": false
+}

schema/c2s/send.json

@@ -0,0 +1,22 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://git.eeqj.de/sneak/chat/schema/c2s/send.json",
+  "title": "C2S Send",
+  "description": "Send a message to a channel or user. Submitted via POST /api/v1/messages.",
+  "type": "object",
+  "properties": {
+    "to": {
+      "type": "string",
+      "description": "Target: channel name (prefixed with #) or nick for DM.",
+      "examples": ["#general", "alice"]
+    },
+    "content": {
+      "type": "string",
+      "description": "Message body (UTF-8 text).",
+      "minLength": 1,
+      "maxLength": 4096
+    }
+  },
+  "required": ["to", "content"],
+  "additionalProperties": false
+}

schema/c2s/topic.json

@@ -0,0 +1,21 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://git.eeqj.de/sneak/chat/schema/c2s/topic.json",
+  "title": "C2S Topic",
+  "description": "Set a channel's topic.",
+  "type": "object",
+  "properties": {
+    "channel": {
+      "type": "string",
+      "description": "Target channel.",
+      "pattern": "^#[a-zA-Z0-9_-]+$"
+    },
+    "topic": {
+      "type": "string",
+      "description": "New topic text. Empty string clears the topic.",
+      "maxLength": 512
+    }
+  },
+  "required": ["channel", "topic"],
+  "additionalProperties": false
+}