W70: Wire viewer menubar stubs — bookmarks, nav, close

Eliminate the last 6 known stubs in the viewer menubar dispatch.
Previously BookmarkToggle/BookmarkNext/BookmarkPrev/NextFile/
PrevFile/Close were documented as 'planned follow-up' stubs.
Now fully wired to existing keyboard handlers:

- BookmarkToggle: set bookmark at current position
- BookmarkNext/Prev: navigate bookmarks
- NextFile/PrevFile: file navigation
- Close: sets should_close flag consumed by handle_viewer_key

Tests: 1427 pass, zero warnings.

local/recipes/tui/tlc/source/src/filemanager/mod.rs

@@ -710,7 +710,7 @@ impl FileManager {
     /// viewer was closed.
     pub fn handle_viewer_key(&mut self, key: Key) -> bool {
         if let Some(v) = &mut self.viewer {
-            let closed = v.handle_key(key);
+            let closed = v.handle_key(key) || v.should_close;
             if closed {
                 v.save_cursor_position();
             }

local/recipes/tui/tlc/source/src/viewer/mod.rs

@@ -117,6 +117,8 @@ pub struct Viewer {
     pub nroff_enabled: bool,
     /// Whether to show the F1 help overlay.
     pub show_help: bool,
+    /// Set by ViewerCmd::Close — the caller should close the viewer.
+    pub should_close: bool,
     /// Active modal prompt at the bottom of the viewer (`None` =
     /// no prompt open). Drives the prompt's title and Enter
     /// handler.
@@ -198,6 +200,7 @@ impl Viewer {
             hexview_in_text: false,
             nroff_enabled: false,
             show_help: false,
+            should_close: false,
             prompt: None,
             prompt_input: String::new(),
             loading: size >= crate::viewer::source::INLINE_THRESHOLD,
@@ -246,6 +249,7 @@ impl Viewer {
             hexview_in_text: false,
             nroff_enabled: false,
             show_help: false,
+            should_close: false,
             prompt: None,
             prompt_input: String::new(),
             loading: size >= crate::viewer::source::INLINE_THRESHOLD,
@@ -1250,16 +1254,32 @@ impl Viewer {
                 self.prompt = Some(ViewerPrompt::GotoLine);
                 self.prompt_input.clear();
             }
-            ViewerCmd::BookmarkToggle
-            | ViewerCmd::BookmarkNext
-            | ViewerCmd::BookmarkPrev
-            | ViewerCmd::NextFile
-            | ViewerCmd::PrevFile
-            | ViewerCmd::Close => {
-                // Bookmark / file navigation / close are not yet
-                // wired to menubar commands. They are still reachable
-                // via their keyboard shortcuts. This is a planned
-                // follow-up.
+            ViewerCmd::BookmarkToggle => {
+                self.marks[self.marker] = Some(self.top);
+                self.marker = (self.marker + 1) % 10;
+            }
+            ViewerCmd::BookmarkNext => {
+                self.marker = (self.marker + 1) % 10;
+                if let Some(pos) = self.marks[self.marker] {
+                    self.top = pos;
+                    self.sync_cursor_to_top();
+                }
+            }
+            ViewerCmd::BookmarkPrev => {
+                let slot = self.marker.checked_sub(1).unwrap_or(9);
+                if let Some(pos) = self.marks[slot] {
+                    self.top = pos;
+                    self.sync_cursor_to_top();
+                }
+            }
+            ViewerCmd::NextFile => {
+                let _ = self.open_next();
+            }
+            ViewerCmd::PrevFile => {
+                let _ = self.open_prev();
+            }
+            ViewerCmd::Close => {
+                self.should_close = true;
             }
         }
     }