refactored internal documentation and simplified comments across chat BLoCs, file viewer, and navigation components

lib/view/pages/talk/widgets/highlighted_linkify.dart

@@ -78,9 +78,8 @@ class HighlightedLinkify extends StatefulWidget {
 }
 
 class _HighlightedLinkifyState extends State<HighlightedLinkify> {
-  // Cached per link text so character-by-character search rebuilds don't
-  // churn through allocate/dispose on every keystroke. Stale entries are
-  // pruned at the end of each build via [_seenLinkKeys].
+  // Cached per link text — search rebuilds keystroke-by-keystroke
+  // would otherwise churn allocate/dispose. Pruned via [_seenLinkKeys].
   final Map<String, TapGestureRecognizer> _recognizers = {};
   final Set<String> _seenLinkKeys = {};
 
@@ -97,8 +96,7 @@ class _HighlightedLinkifyState extends State<HighlightedLinkify> {
     final key = el.text;
     final existing = _recognizers[key];
     if (existing != null) {
-      // Refresh onTap so a new widget.onOpen callback (from a parent
-      // rebuild) picks up the latest closure.
+      // Refresh onTap so a parent rebuild's new closure is picked up.
       existing.onTap = () => widget.onOpen?.call(el);
       return existing;
     }
@@ -124,14 +122,9 @@ class _HighlightedLinkifyState extends State<HighlightedLinkify> {
     final defaultStyle = widget.style ??
         Theme.of(context).textTheme.bodyMedium ??
         DefaultTextStyle.of(context).style;
-    // Start from the surrounding text style so links inherit font family,
-    // size, weight, etc., then layer the link-specific color and underline
-    // on top. (Going the other way around — link style as base — used to
-    // work because TextStyle.copyWith treats `null` as "leave unchanged",
-    // so the explicit `color: null, decoration: null` were silently
-    // ignored and the merge pulled defaultStyle's color/decoration over
-    // the blue + underline. Result: links rendered in body-text color
-    // with no underline.)
+    // Default first, link style on top — reversing the merge silently
+    // drops link color/underline because TextStyle.merge treats explicit
+    // nulls in the overlay as "leave unchanged".
     final linkStyle = defaultStyle.merge(
       widget.linkStyle ??
           const TextStyle(