feat(examples): add hemx html pattern gallery

Add examples/html_examples as a copy-pasteable gallery for the first htmx-style HTML UX patterns using exact htmx URL slugs in the page and README. The slice covers click-to-edit, edit-row, delete-row, inline-validation, click-to-load, and active-search with .heml templates, generated resources, server-owned Rust state, and runtime-free selector targeting.

req: htmx_equivalents/001

req: htmx_equivalents/002

req: examples/001

examples/html_examples/templates/partials/editable_row.heml

@@ -0,0 +1,14 @@
+<tr +data-key="self.id">
+  <td h-if="!self.editing">{+ self.title +}</td>
+  <td h-if="!self.editing">
+    <form data-hemx-handle="edit_row" data-hemx-form="edit_row"><button type="submit" name="id" +value="self.id">Edit</button></form>
+    <form data-hemx-handle="delete_row" data-hemx-form="delete_row"><button type="submit" name="id" +value="self.id">Delete</button></form>
+  </td>
+  <td h-if="self.editing" colspan="2">
+    <form data-hemx-handle="save_row" data-hemx-form="save_row">
+      <input type="hidden" name="id" +value="self.id">
+      <label>Task <input name="title" +value="self.title" required="required"></label>
+      <button type="submit">Save</button>
+    </form>
+  </td>
+</tr>