fix(parser): add {#if}/{#else}/{/if} support and raw-text <style>/<script> in HTML templates

The El lexer silently skips '#', so {#each} lexes as LBrace Ident:"each"
and {#if} lexes as LBrace If ... (using the If keyword token, not Hash).
The existing {#each} check used k2=="Hash" which was dead code.

Parser changes (parser.el):
- Add parse_raw_text_content(): collects all tokens as raw text until
  </tag_name>, bypassing El expression parsing. Used for <style> and
  <script> elements so CSS/JS content isn't parsed as El expressions.
- parse_html_element(): use raw-text mode for <style> and <script> tags.
- parse_html_children(): fix {#each} detection (k2=="Ident", k3=="each"
  instead of dead k2=="Hash" check). Add {#if cond}...{#else}...{/if}
  support generating HtmlIf AST nodes.

Codegen changes (codegen.el):
- Add cg_html_if(): generates if (cond_c) { then_c } else { else_c }
  for HtmlIf nodes.
- cg_html_parts(): dispatch HtmlIf to cg_html_if.

lang/el-compiler/src/codegen.el

@@ -324,6 +324,10 @@ fn cg_html_parts(children: [Map<String, Any>], acc_var: String) -> String {
             let each_c: String = cg_html_each(child, acc_var)
             let parts = native_list_append(parts, each_c)
         }
+        if str_eq(html_kind, "HtmlIf") {
+            let if_c: String = cg_html_if(child, acc_var)
+            let parts = native_list_append(parts, if_c)
+        }
         let i = i + 1
     }
     str_join(parts, "")
@@ -413,6 +417,17 @@ fn cg_html_each(node: Map<String, Any>, acc_var: String) -> String {
     "{ el_val_t " + list_var + " = (" + list_c + "); el_val_t " + len_var + " = el_list_len(" + list_var + "); for (el_val_t " + idx_var + " = 0; " + idx_var + " < " + len_var + "; " + idx_var + "++) { el_val_t " + item_name + " = el_list_get(" + list_var + ", " + idx_var + "); " + inner_c + "} } "
 }
 
+// Generate code for {#if cond} ... {/if} (with optional {#else}).
+fn cg_html_if(node: Map<String, Any>, acc_var: String) -> String {
+    let cond_expr = node["cond"]
+    let then_children: [Map<String, Any>] = node["then"]
+    let else_children: [Map<String, Any>] = node["else"]
+    let cond_c: String = cg_expr(cond_expr)
+    let then_c: String = cg_html_parts(then_children, acc_var)
+    let else_c: String = cg_html_parts(else_children, acc_var)
+    "if (" + cond_c + ") { " + then_c + " } else { " + else_c + " } "
+}
+
 // Top-level HTML template codegen — returns a C statement-expression string.
 fn cg_html_template(expr: Map<String, Any>) -> String {
     let root = expr["root"]