feat: codespace tab names and session widget improvements

Show friendly codespace name (without trailing random ID) in tmux tabs,
prefixed with cs:. Add ctrl-n to session widget to start a new copilot
session, and improve header labels and field display.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

home/.tmux/tab-name.sh

@@ -12,6 +12,16 @@ case "$cmd" in
     *) name="$cmd" ;;
 esac
 
+# In Codespaces, show friendly name without trailing random ID
+# Codespace names: "adjective-noun-id" where id is alphanumeric gibberish
+if [[ -n "$CODESPACE_NAME" ]]; then
+    friendly="${CODESPACE_NAME%-*}"
+    # If no hyphen was found, use full name
+    [[ "$friendly" == "$CODESPACE_NAME" ]] && friendly="$CODESPACE_NAME"
+    echo "cs:${friendly}"
+    exit 0
+fi
+
 if (( ${#name} > max )); then
     echo "${name:0:$max}…"
 else

home/.zsh/widgets.zsh

@@ -284,12 +284,20 @@ for line in sys.stdin:
         print(\">\", msg)
     except: pass
 " 2>/dev/null
-        '  --header 'enter=colby | ctrl-r=restricted | ctrl-s=continue latest' \
-           --expect=ctrl-r,ctrl-s)"
+        ' --delimiter="|" --with-nth=1,3 \
+           --header 'enter=resume | ^r=restricted | ^s=latest | ^n=new' \
+           --expect=ctrl-r,ctrl-s,ctrl-n)"
         local fzf_rc=$?
-        [[ $fzf_rc -ne 0 && "$session" != ctrl-s* ]] && { zle reset-prompt; return; }
+        [[ $fzf_rc -ne 0 && "$session" != ctrl-s* && "$session" != ctrl-n* ]] && { zle reset-prompt; return; }
         local key=$(echo "$session" | head -1)
         local line=$(echo "$session" | tail -1)
+        # Ctrl+N — new session
+        if [[ "$key" == "ctrl-n" ]]; then
+            BUFFER="colby"
+            zle reset-prompt
+            zle accept-line
+            return
+        fi
         # Ctrl+S again — continue latest
         if [[ "$key" == "ctrl-s" ]]; then
             BUFFER="colby --continue"