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/base64_demo.wren

@@ -0,0 +1,68 @@
+// retoor <retoor@molodetz.nl>
+
+import "base64" for Base64
+
+System.print("=== Base64 Module Demo ===\n")
+
+System.print("--- Basic Encoding ---")
+var text = "Hello, World!"
+var encoded = Base64.encode(text)
+System.print("Original: %(text)")
+System.print("Encoded: %(encoded)")
+
+System.print("\n--- Basic Decoding ---")
+var decoded = Base64.decode(encoded)
+System.print("Decoded: %(decoded)")
+
+System.print("\n--- Various Strings ---")
+var samples = [
+  "Hello",
+  "The quick brown fox jumps over the lazy dog",
+  "12345",
+  "Special chars: !@#^&*()",
+  "Unicode: cafe resume naive"
+]
+
+for (sample in samples) {
+  var enc = Base64.encode(sample)
+  var dec = Base64.decode(enc)
+  System.print("%(sample)")
+  System.print("  -> %(enc)")
+  System.print("  <- %(dec)")
+  System.print("")
+}
+
+System.print("--- URL-Safe Encoding ---")
+var urlData = "Hello+World/Test=End"
+var urlEncoded = Base64.encodeUrl(urlData)
+var standardEncoded = Base64.encode(urlData)
+System.print("Original: %(urlData)")
+System.print("Standard Base64: %(standardEncoded)")
+System.print("URL-Safe Base64: %(urlEncoded)")
+
+System.print("\n--- URL-Safe Decoding ---")
+var urlDecoded = Base64.decodeUrl(urlEncoded)
+System.print("Decoded from URL-safe: %(urlDecoded)")
+
+System.print("\n--- Binary-like Data ---")
+var binaryText = "Binary: \x00\x01\x02\xFF"
+var binaryEncoded = Base64.encode(binaryText)
+System.print("Binary-like string encoded: %(binaryEncoded)")
+
+System.print("\n--- Empty String ---")
+System.print("Empty encoded: %(Base64.encode(""))")
+System.print("Empty decoded: %(Base64.decode(""))")
+
+System.print("\n--- Practical Example: Basic Auth Header ---")
+var username = "admin"
+var password = "secret123"
+var credentials = "%(username):%(password)"
+var authHeader = "Basic " + Base64.encode(credentials)
+System.print("Credentials: %(credentials)")
+System.print("Authorization header: %(authHeader)")
+
+System.print("\n--- Practical Example: Data URI ---")
+var jsonData = "{\"message\":\"Hello\"}"
+var dataUri = "data:application/json;base64," + Base64.encode(jsonData)
+System.print("JSON: %(jsonData)")
+System.print("Data URI: %(dataUri)")