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-state.org

@@ -41,6 +41,7 @@ All state mutation flows through event handlers in the controller.
     :connected :green :disconnected :red :busy :magenta :idle :white
     ;; Gate trace
     :gate-passed :green :gate-blocked :red :gate-approval :yellow
+    :hitl :magenta
     ;; Tools (future use)
     :tool-running :magenta :tool-success :green :tool-failure :red :tool-output :white
     ;; Display
@@ -168,8 +169,8 @@ See *tui-theme-presets* for named presets (dark, light, solarized, gruvbox).")
         (setf (st :input-buffer) (reverse (coerce new 'list)))
         (setf (st :cursor-pos) (1- pos))))))
 
-(defun add-msg (role content &key gate-trace)
-  (vector-push-extend (list :role role :content content :time (now) :gate-trace gate-trace) (st :messages))
+(defun add-msg (role content &key gate-trace panel)
+  (vector-push-extend (list :role role :content content :time (now) :gate-trace gate-trace :panel panel) (st :messages))
   ;; v0.7.0: notify when scrolled up and new msg arrives
   (unless (st :scroll-at-bottom)
     (setf (st :scroll-notify) t))