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>

docs/devdesk.1

@@ -7,6 +7,10 @@ devdesk \- persistent Claude Code sessions in tmux, shared by the browser and SS
 .br
 .B devdesk new
 .I NAME
+.RI [ PROJECT ]
+.br
+.B devdesk rename
+.I OLD NEW
 .br
 .B devdesk ls
 .br
@@ -26,16 +30,20 @@ resumes its own conversation.
 .SH COMMANDS
 .TP
 .B attach \fR[\fINAME\fR]
-Attach to session \fINAME\fR, creating it if needed. The default session
-(\fBmain\fR) uses the projects root; other names map to the project directory of
-that name or slug (\(lqtest code\(rq becomes \fBtest-code\fR). Without \fINAME\fR,
-opens the picker.
+Attach to session \fINAME\fR, creating it if needed. Names matching a project
+folder (or its slug: \(lqtest code\(rq becomes \fBtest-code\fR) start there; any
+other name starts in \fBDEVDESK_DEFAULT_DIR\fR. Without \fINAME\fR, opens the picker.
 .TP
 .B attach --list
 Print sessions and projects as JSON (used by the web UI).
 .TP
-.B new \fINAME\fR
-Create session \fINAME\fR detached, if it does not exist.
+.B new \fINAME\fR [\fIPROJECT\fR]
+Create session \fINAME\fR detached, in \fIPROJECT\fR's folder if given, otherwise
+in the folder its name maps to (a project of that name, or \fBDEVDESK_DEFAULT_DIR\fR).
+.TP
+.B rename \fIOLD NEW\fR
+Rename a running or dormant session; Claude keeps running and its recorded
+conversation moves with it.
 .TP
 .B ls
 List running (\(bu) and dormant (\(ci) sessions.