Render file reference as link with file preview on hover/click in web app

Overview
- Khoj references files it used in its response as markdown links.
  For example [1](file://path/to/file.txt#line=121)
- Previously these file links were just shown as raw text
- This change renders khoj's inline file references as a proper links
  and shows file content preview (around specified line if deeplink)
  on hover or click in the web app

Details
- Render inline file references as links in chat message on web app.
  Previously references like [1](file://path/to/file.txt#line=120)
  would be shown as plain text. Now they are rendered as links
- Preview file content of referenced files on click or hover.
  If reference uses a deeplink with line number, the file content
  around that line is shown on hover, click. Click allows viewing file
  preview on mobile, unlike hover. Hover is easier with mouse.

src/interface/web/app/components/chatMessage/chatMessage.module.css

@@ -23,6 +23,22 @@ div.chatMessageWrapper a span {
     display: revert !important;
 }
 
+/* File link styling */
+.chatMessageWrapper a.file-link {
+    color: hsl(var(--primary));
+    text-decoration: underline;
+    cursor: pointer;
+    transition: color 0.2s ease;
+}
+
+.chatMessageWrapper a.file-link:hover {
+    color: hsl(var(--primary-foreground));
+    background-color: hsl(var(--primary));
+    text-decoration: none;
+    padding: 2px 4px;
+    border-radius: 4px;
+}
+
 div.khojfullHistory {
     padding-left: 4px;
 }