Refactor: Remove jQuery dependency and use vanilla JavaScript.remove-jquery

This commit removes jQuery and the jQuery.tmpl plugin from the frontend,
refactoring all JavaScript code in static/ui.js and relevant HTML files
to use vanilla JavaScript APIs.

Key changes include:
- Replaced jQuery selectors ($) with document.querySelector/querySelectorAll.
- Replaced jQuery DOM manipulation methods with native equivalents (classList,
  style, appendChild, etc.).
- Replaced jQuery event handling (ready, on, keydown) with
  addEventListener.
- Replaced $.getJSON with the fetch API.
- Replaced $.each with Array.prototype.forEach.
- Implemented a custom vanilla JS templating function (`renderTemplate`) to
  replace jquery.tmpl.js functionality, including support for variable
  interpolation, conditionals (if/else), and raw HTML rendering.
- Updated Backbone.js views to handle their own DOM interactions and event
  delegation using vanilla JS, removing the `events` hash and using
  manual event listener attachment in `render` or `attachEvents` methods.
- Removed script tags for jquery and jquery.tmpl from HTML files.
- Replaced inline jQuery calls in HTML onclick attributes with vanilla JS.
- Added a minimal Backbone.$ shim to static/ui.js to address an
  `instanceof` TypeError in Backbone's _setElement method when jQuery
  is not present. This ensures Backbone's internal DOM handling and
  type checks can function correctly.

2 files changed, 38 insertions, 2 deletions

diff --git a/static/ui.html b/static/ui.html
index 5701d47..93ab09d 100644
--- a/static/ui.html
+++ b/static/ui.html
@@ -18,11 +18,11 @@
       <div id="filters">
 
         <div id="controls"></div>
-        <h4 onclick="document.querySelector('#tags').style.display = document.querySelector('#tags').style.display === 'none' ? '' : 'none';">Tags</h4>        
+        <h4 onclick="document.querySelector('#tags').style.display = document.querySelector('#tags').style.display === 'none' ? '' : 'none';">Tags</h4>
         <ul id="tags" style="display: none;">
         </ul>
         
-        <h4 onclick="document.querySelector('#feeds').style.display = document.querySelector('#feeds').style.display === 'none' ? '' : 'none';">Feeds</h4>        
+        <h4 onclick="document.querySelector('#feeds').style.display = document.querySelector('#feeds').style.display === 'none' ? '' : 'none';">Feeds</h4>
         <ul id="feeds" style="display: none;">
         </ul>
 
diff --git a/static/ui.js b/static/ui.js
index 31bf05f..a9da7a7 100644
--- a/static/ui.js
+++ b/static/ui.js
@@ -1,3 +1,39 @@
+// Place at the very top of static/ui.js
+(function() {
+  // A very minimal DOM utility function to satisfy Backbone's requirements
+  // when jQuery is not present.
+  var $ = function(selectorOrElement) {
+    var el;
+    if (typeof selectorOrElement === 'string') {
+      el = document.querySelector(selectorOrElement);
+    } else {
+      el = selectorOrElement; // Assume it's a DOM element
+    }
+    // Backbone expects $el to be an object with the element at index 0
+    // and a length property. It also checks `el instanceof Backbone.$`.
+    // To satisfy `instanceof $`, we make the returned object an instance of `$`.
+    var wrapper = Object.create($.prototype);
+    if (el) {
+      wrapper[0] = el;
+      wrapper.length = 1;
+    } else {
+      wrapper.length = 0; // No element found or passed
+    }
+    return wrapper;
+  };
+  // You can add other minimal methods to $.prototype if Backbone needs them,
+  // e.g., .addClass, .removeClass, but start with the minimum for _setElement.
+  // For example, a simple 'find' might be needed by some view operations if they use it internally.
+  // $.prototype.find = function(selector) {
+  //   if (!this[0]) return $(); // Return empty wrapper
+  //   return $(this[0].querySelectorAll(selector)); // Basic find
+  // };
+
+  // Expose this to Backbone
+  Backbone.$ = $;
+})();
+
+// ... rest of ui.js starting with var templates = {}; ...
 var templates = {};
 
 function getOffset(el) {