feat: add cJSON and SQLite amalgamation source files under deps/

Add the cJSON library (cJSON.c, cJSON.h) and SQLite amalgamation
(sqlite3.c, sqlite3.h, sqlite3ext.h, shell.c) as vendored dependencies
in the deps/ directory for use by the project build system.

example/websocket_chat_client.wren

@@ -0,0 +1,49 @@
+// retoor <retoor@molodetz.nl>
+
+import "websocket" for WebSocket
+import "scheduler" for Scheduler
+import "timer" for Timer
+import "io" for Stdin
+
+var host = "ws://127.0.0.1:8080"
+
+System.print("=== WebSocket Chat Client ===")
+System.print("Connecting to %(host)...")
+
+var ws = WebSocket.connect(host)
+System.print("Connected!")
+System.print("Commands: /name <name>, /who, /quit")
+System.print("Type a message and press Enter to send.\n")
+
+var running = true
+
+Scheduler.add {
+  while (running && ws.isOpen) {
+    var msg = ws.receive()
+    if (msg == null || msg.isClose) {
+      running = false
+      System.print("\nConnection closed.")
+      break
+    }
+    if (msg.isText) {
+      System.print(msg.text)
+    }
+  }
+}
+
+Timer.sleep(100)
+
+while (running && ws.isOpen) {
+  System.write("> ")
+  var line = Stdin.readLine()
+  if (line == null || line == "/quit") {
+    running = false
+    break
+  }
+  if (line.count > 0) {
+    ws.send(line)
+  }
+}
+
+ws.close()
+System.print("Disconnected.")