v0.7.2: gate-trace wiring, HITL panels, /identity command — TDD

Gate trace: wired into view-chat, renders below agent messages in dim.
Collapsed-gates state field for Tab toggle (deferred to Croatoan test).

HITL panels: on-daemon-msg detects :approval-required events, renders
styled panel messages with :panel flag. View-chat renders with :hitl
theme color (magenta). /approve and /deny add confirmation messages.

/identity: opens ~/memex/IDENTITY.org in emacsclient -c -a '', auto-reloads.

- channel-tui-view: gate-trace in view-chat, HITL panel styling
- channel-tui-state: :collapsed-gates, :hitl theme, :panel attr
- channel-tui-main: HITL panel detection, /identity handler
- View: 29/29  TUI Main: 83/84 (1 pre-existing flake)

org/channel-tui-view.org

@@ -132,9 +132,13 @@ Returns list of trimmed strings. Single words wider than width are split."
                         (time (or (getf msg :time) ""))
                         (color (theme-color (case role (:user :user) (:agent :agent) (:system :system) (t :agent))))
                         (prefix (case role (:user "⬆") (:agent "⬇") (t "  ")))
+                        (is-panel (getf msg :panel))
                         (line-text (format nil "~a [~a] ~a" prefix time content))
                         (wrapped (word-wrap line-text (- w 2))))
-                    (dolist (line wrapped)
+                   ;; HITL panel: render with colored border
+                   (when is-panel
+                     (setf color (theme-color :hitl)))
+                   (dolist (line wrapped)
                       (when (< y (1- h))
                         (if (eq role :agent)
                             (let ((segments (parse-markdown-spans line)))