feat: free-form sessions, rename/end from the panel, live Claude Context (0.2.0)

- Sessions no longer need a project folder: any name works and starts in
  DEVDESK_DEFAULT_DIR unless it matches a project; `devdesk new NAME [PROJECT]`.
- Rename (✎) and end/forget (×) sessions from the Sessions panel, plus
  `devdesk rename`. The browser runs them as `devdesk attach --new|--rename|--end`
  through ttyd. Renames keep the running Claude and its recorded conversation:
  the hook, the run-wrapper and the statusline ask tmux for the current name.
- Claude Context panel is live: devdesk-statusline snapshots model,
  context-window use, cost and edits per session, which --list reports;
  Claude's footer gets a one-line summary. The panel now sits under Sessions.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libexec/devdesk-claude-run

@@ -7,7 +7,9 @@ set -uo pipefail
 # shellcheck source=libexec/devdesk-lib.sh
 . "${DEVDESK_LIBEXEC:-/usr/lib/devdesk}/devdesk-lib.sh"
 
-NAME=${DEVDESK_SESSION:?DEVDESK_SESSION is not set}
+NAME=$(dd_current_session)
+[ -n "$NAME" ] || dd_die "not running inside a DevDesk session"
+
 CLAUDE_BIN=${CLAUDE_BIN:-claude}
 SETTINGS="$DEVDESK_SHARE/claude-settings.json"
 read -r -a EXTRA <<<"${CLAUDE_ARGS:-}"
@@ -63,8 +65,10 @@ menu() {
 printf '\033]2;%s\033\134' "$NAME" # pane title (ST = ESC \\)
 mode=resume
 while :; do
+    NAME=$(dd_current_session) # follow renames
     if [ "$mode" = new ]; then run_new; else run_resume; fi
     rc=$?
+    NAME=$(dd_current_session)
     while :; do
         menu "$rc"
         IFS= read -rsn1 key || exit 0