feat: add async/await keywords, Num/String extensions, and Jinja markdown example

Add `async` and `await` token support to the Wren compiler with scheduler resolution logic, extend `Num` with `e` constant, hyperbolic trig, base conversion, and new methods (`isZero`, `gcd`, `lcm`, `digits`, etc.), extend `String` with `lower`, `upper`, `capitalize`, `title`, and regenerate `wren_core.wren.inc`. Include `Makefile` for multi-platform builds, rewrite `README.md` with updated build instructions, and add `example/await_demo.wren` and `example/jinja_markdown.wren` demonstrating new features.

manual/api/index.html

@@ -40,6 +40,8 @@
                     <span class="section-title">API Reference</span>
                     <ul>
                         <li><a href="index.html" class="active">Overview</a></li>
+                        <li><a href="string.html">String</a></li>
+                        <li><a href="number.html">Num</a></li>
                         <li><a href="http.html">http</a></li>
                         <li><a href="websocket.html">websocket</a></li>
                         <li><a href="tls.html">tls</a></li>
@@ -58,6 +60,7 @@
                         <li><a href="datetime.html">datetime</a></li>
                         <li><a href="timer.html">timer</a></li>
                         <li><a href="io.html">io</a></li>
+                        <li><a href="pathlib.html">pathlib</a></li>
                         <li><a href="scheduler.html">scheduler</a></li>
                         <li><a href="math.html">math</a></li>
                         <li><a href="uuid.html">uuid</a></li>
@@ -104,12 +107,26 @@
             <article>
                 <h1>API Reference</h1>
 
-                <p>Wren-CLI provides 28 built-in modules covering networking, file I/O, data processing, system operations, and more. All modules are imported using the <code>import</code> statement.</p>
+                <p>Wren-CLI provides 29 built-in modules covering networking, file I/O, data processing, system operations, and more. All modules are imported using the <code>import</code> statement.</p>
 
                 <pre><code>import "http" for Http
 import "json" for Json
 import "io" for File</code></pre>
 
+                <h2>Core Types</h2>
+                <p>Extended methods on built-in types, available without imports.</p>
+
+                <div class="card-grid">
+                    <div class="card">
+                        <h3><a href="string.html">String</a></h3>
+                        <p>Case conversion, character testing, padding, splitting, reversing, and more on all strings.</p>
+                    </div>
+                    <div class="card">
+                        <h3><a href="number.html">Num</a></h3>
+                        <p>Query predicates, hyperbolic functions, base conversion, formatting, GCD/LCM, and more on all numbers.</p>
+                    </div>
+                </div>
+
                 <h2>Networking</h2>
                 <p>Modules for HTTP, WebSocket, and low-level network operations.</p>
 
@@ -198,6 +215,10 @@ import "io" for File</code></pre>
                         <h3><a href="io.html">io</a></h3>
                         <p>File and directory operations, stdin/stdout handling.</p>
                     </div>
+                    <div class="card">
+                        <h3><a href="pathlib.html">pathlib</a></h3>
+                        <p>Object-oriented filesystem paths with glob, walk, and tree operations.</p>
+                    </div>
                 </div>
 
                 <h2>Data & Time</h2>
@@ -345,6 +366,11 @@ import "io" for File</code></pre>
                         <td>File, Directory, Stdin, Stdout</td>
                         <td>File I/O</td>
                     </tr>
+                    <tr>
+                        <td><a href="pathlib.html">pathlib</a></td>
+                        <td>Path, PurePath</td>
+                        <td>Filesystem paths</td>
+                    </tr>
                     <tr>
                         <td><a href="scheduler.html">scheduler</a></td>
                         <td>Scheduler</td>