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/lib/functions/tn

@@ -0,0 +1,31 @@
+#!/usr/bin/env sh
+
+function tn {
+    if [ -z "$TMUX" ]; then
+        echo "Not in a tmux session"
+        return 1
+    fi
+
+    base=$(basename "$PWD")
+    current=$(tmux display-message -p '#{session_name}')
+
+    # Don't rename if already named correctly
+    if [ "$current" = "$base" ]; then
+        echo "Session already named '$base'"
+        return 0
+    fi
+
+    if tmux has-session -t "$base" 2>/dev/null; then
+        i=2
+        while tmux has-session -t "${base}-${i}" 2>/dev/null; do
+            i=$((i+1))
+        done
+        tmux rename-session "${base}-${i}"
+        echo "Renamed session to '${base}-${i}'"
+    else
+        tmux rename-session "$base"
+        echo "Renamed session to '$base'"
+    fi
+}
+
+tn "$@"

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
+"'