Fix tmux auto-naming for duplicate directory basenames

- Handle duplicate session names by appending -2, -3, etc.
- Add tn function to manually rename current session to cwd basename

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

dotfiles/tmux.conf

@@ -1,5 +1,28 @@
 # Automatically rename new sessions to the basename of the current directory
-set-hook -g session-created 'run-shell "tmux rename-session -t #{session_name} $(basename #{pane_current_path})"'
+# Handles duplicates by appending -2, -3, etc.
+set-hook -g session-created 'run-shell "
+  base=$(basename \"#{pane_current_path}\")
+  if tmux has-session -t \"$base\" 2>/dev/null; then
+    i=2
+    while tmux has-session -t \"${base}-${i}\" 2>/dev/null; do
+      i=$((i+1))
+    done
+    tmux rename-session -t \"#{session_name}\" \"${base}-${i}\"
+  else
+    tmux rename-session -t \"#{session_name}\" \"$base\"
+  fi
+"'
 
 # Also rename when attaching to a session (optional)
-set-hook -g client-session-changed 'run-shell "tmux rename-session -t #{session_name} $(basename #{pane_current_path})"'
+set-hook -g client-session-changed 'run-shell "
+  base=$(basename \"#{pane_current_path}\")
+  if tmux has-session -t \"$base\" 2>/dev/null; then
+    i=2
+    while tmux has-session -t \"${base}-${i}\" 2>/dev/null; do
+      i=$((i+1))
+    done
+    tmux rename-session -t \"#{session_name}\" \"${base}-${i}\"
+  else
+    tmux rename-session -t \"#{session_name}\" \"$base\"
+  fi
+"'