feat: anchor links (#1765)

* feat: add heading extension with unique ID support and scroll functionality
* Added unique id for heading
* remove baseUrl heading storage
* move heading to extensions package
* WIP
* support anchors in mentions
* enhance scrolling functionality
* nodeId function
* fix nanoid import
* Bring unique-id extension local
* fixes
* fix internal link scroll in public pages
* add unique id server side
* rename mention anchor to anchorId
* capture first anchorId on paste

---------

Co-authored-by: Romik <40670677+RomikMakavana@users.noreply.github.com>

apps/client/src/features/editor/styles/core.css

@@ -186,6 +186,39 @@
     margin-left: auto;
     margin-right: auto;
   }
+
+}
+
+.ProseMirror > h1,
+.ProseMirror > h2,
+.ProseMirror > h3,
+.ProseMirror > h4,
+.ProseMirror > h5,
+.ProseMirror > h6 {
+  
+  > .link-btn {
+    cursor: pointer;
+    position: relative;
+
+  }
+  
+  > .link-btn > .link-btn-content {
+    opacity: 0;
+    position: absolute;
+    left: 5px;
+    top: 0;
+    height: 100%;
+    transition: opacity 0.15s ease;
+    display: inline-flex;
+    justify-content: center;
+    flex-direction: column;
+  }
+  
+  &:hover > .link-btn > .link-btn-content {
+    opacity: 1;
+  }
+
+  scroll-margin-top: 80px; /* match your header height */
 }
 
 .ProseMirror-icon {