Add frontmatter, markdown, path, xml, rss, and web packages

Sync local packages into the registry repo and update index.json
and README.md to include all 9 packages.

packages/xml/lib.lux

@@ -0,0 +1,109 @@
+// xml - XML builder for Lux
+//
+// Provides a simple API for constructing well-formed XML documents.
+// Designed for generating RSS feeds, sitemaps, and other XML output.
+
+// An XML attribute (key-value pair)
+type Attr =
+    | Attr(String, String)
+
+// An XML node: element with tag, attributes, and children, or text content
+type Node =
+    | Element(String, List<Attr>, List<Node>)
+    | Text(String)
+    | CData(String)
+    | Raw(String)
+
+// Escape special XML characters in text content
+pub fn escape(s: String): String =
+    String.replace(
+        String.replace(
+            String.replace(
+                String.replace(
+                    String.replace(s, "&", "&amp;"),
+                    "<", "&lt;"),
+                ">", "&gt;"),
+            "\"", "&quot;"),
+        "'", "&apos;")
+
+// Create a text node
+pub fn text(content: String): Node = Text(content)
+
+// Create a CDATA section
+pub fn cdata(content: String): Node = CData(content)
+
+// Create a raw (unescaped) node
+pub fn raw(content: String): Node = Raw(content)
+
+// Create an element with tag, attributes, and children
+pub fn element(tag: String, attrs: List<Attr>, children: List<Node>): Node =
+    Element(tag, attrs, children)
+
+// Create an element with no attributes
+pub fn el(tag: String, children: List<Node>): Node =
+    Element(tag, [], children)
+
+// Create a self-closing element with attributes and no children
+pub fn selfClosing(tag: String, attrs: List<Attr>): Node =
+    Element(tag, attrs, [])
+
+// Create an attribute
+pub fn attr(key: String, value: String): Attr =
+    Attr(key, value)
+
+// Create an element with text content
+pub fn textEl(tag: String, content: String): Node =
+    Element(tag, [], [Text(content)])
+
+// Create an element with attributes and text content
+pub fn textElAttr(tag: String, attrs: List<Attr>, content: String): Node =
+    Element(tag, attrs, [Text(content)])
+
+// Render a single attribute to string
+fn renderAttr(a: Attr): String =
+    match a {
+    Attr(k, v) => " " + k + "=\"" + escape(v) + "\"",
+}
+
+// Render a list of attributes to string
+fn renderAttrs(attrs: List<Attr>): String =
+    match List.head(attrs) {
+    None => "",
+    Some(a) => renderAttr(a) + match List.tail(attrs) {
+        Some(rest) => renderAttrs(rest),
+        None => "",
+    },
+}
+
+// Render child nodes to string
+fn renderChildren(nodes: List<Node>): String =
+    match List.head(nodes) {
+    None => "",
+    Some(node) => render(node) + match List.tail(nodes) {
+        Some(rest) => renderChildren(rest),
+        None => "",
+    },
+}
+
+// Render a node to an XML string
+pub fn render(node: Node): String =
+    match node {
+    Element(tag, attrs, children) => {
+        let attrStr = renderAttrs(attrs)
+        if List.length(children) == 0 then
+            "<" + tag + attrStr + "/>"
+        else
+            "<" + tag + attrStr + ">" + renderChildren(children) + "</" + tag + ">"
+    },
+    Text(content) => escape(content),
+    CData(content) => "<![CDATA[" + content + "]]>",
+    Raw(content) => content,
+}
+
+// Render a complete XML document with declaration
+pub fn document(root: Node): String =
+    "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" + render(root)
+
+// Render with a custom declaration (e.g., for RSS stylesheets)
+pub fn documentWithDecl(decl: String, root: Node): String =
+    decl + "\n" + render(root)