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/openrouter_demo.wren

@@ -0,0 +1,55 @@
+// retoor <retoor@molodetz.nl>
+
+import "http" for Http
+import "json" for Json
+import "env" for Environment
+
+var apiKey = Environment.get("OPENROUTER_API_KEY")
+if (apiKey == null || apiKey.count == 0) {
+  System.print("Error: OPENROUTER_API_KEY environment variable not set")
+  Fiber.abort("Missing API key")
+}
+
+System.print("=== OpenRouter API Demo ===\n")
+
+var model = "x-ai/grok-code-fast-1"
+var prompt = "What is 2 + 2? Reply with just the number."
+
+System.print("Model: %(model)")
+System.print("Prompt: %(prompt)")
+System.print("")
+
+var requestBody = {
+  "model": model,
+  "messages": [
+    {"role": "user", "content": prompt}
+  ]
+}
+
+var headers = {
+  "Authorization": "Bearer " + apiKey,
+  "Content-Type": "application/json"
+}
+
+System.print("Sending request to OpenRouter...")
+
+var response = Http.post("https://openrouter.ai/api/v1/chat/completions", requestBody, headers)
+
+System.print("Status: %(response.statusCode)")
+System.print("")
+
+if (response.ok) {
+  var data = Json.parse(response.body)
+  if (data != null && data["choices"] != null && data["choices"].count > 0) {
+    var message = data["choices"][0]["message"]
+    if (message != null && message["content"] != null) {
+      System.print("Response: %(message["content"])")
+    }
+  }
+  System.print("\nModel used: %(data["model"])")
+  if (data["usage"] != null) {
+    System.print("Tokens - prompt: %(data["usage"]["prompt_tokens"]), completion: %(data["usage"]["completion_tokens"])")
+  }
+} else {
+  System.print("Error: %(response.body)")
+}