feat(gui): Implement Visual DAG with imgui_node_editor

- Add node editor context and config in App.__init__
- Replace tree-based DAG with imgui_node_editor visualization
- Add selection detection for interactive ticket editing
- Add edit panel for selected ticket (view status, target, deps, mark complete, delete)
- Add ui_selected_ticket_id state variable

src/gui_2.py

@@ -23,7 +23,7 @@ from src import models
 from src import app_controller
 
 from pydantic import BaseModel
-from imgui_bundle import imgui, hello_imgui, immapp
+from imgui_bundle import imgui, hello_imgui, immapp, imgui_node_editor as ed
 
 PROVIDERS: list[str] = ["gemini", "anthropic", "gemini_cli", "deepseek"]
 COMMS_CLAMP_CHARS: int = 300
@@ -103,6 +103,10 @@ class App:
   self._api_event_queue_lock = self.controller._api_event_queue_lock
   self._discussion_names_cache: list[str] = []
   self._discussion_names_dirty: bool = True
+  # Initialize node editor context
+  self.node_editor_config = ed.Config()
+  self.node_editor_ctx = ed.create_editor(self.node_editor_config)
+  self.ui_selected_ticket_id: Optional[str] = None
 
  def _handle_approve_tool(self, user_data=None) -> None:
   """UI-level wrapper for approving a pending tool execution ask."""
@@ -1542,25 +1546,46 @@ class App:
   # 4. Task DAG Visualizer
   imgui.text("Task DAG")
   if self.active_track:
-   tickets_by_id = {str(t.get('id') or ''): t for t in self.active_tickets}
-   all_ids = set(tickets_by_id.keys())
-   # Build children map
-   children_map: dict[str, list[str]] = {}
+   ed.set_current_editor(self.node_editor_ctx)
+   ed.begin('Visual DAG')
+   # Selection detection
+   selected = ed.get_selected_nodes()
+   if selected:
+    for node_id in selected:
+     for t in self.active_tickets:
+      if abs(hash(str(t.get('id', '')))) == node_id:
+       self.ui_selected_ticket_id = str(t.get('id', ''))
+       break
+     break
    for t in self.active_tickets:
+    tid = str(t.get('id', '??'))
+    int_id = abs(hash(tid))
+    ed.begin_node(int_id)
+    imgui.text_colored(C_KEY, f"Ticket: {tid}")
+    status = t.get('status', 'todo')
+    s_col = C_VAL
+    if status == 'done' or status == 'complete': s_col = C_IN
+    elif status == 'in_progress' or status == 'running': s_col = C_OUT
+    elif status == 'error': s_col = imgui.ImVec4(1, 0.4, 0.4, 1)
+    imgui.text("Status: ")
+    imgui.same_line()
+    imgui.text_colored(s_col, status)
+    imgui.text(f"Target: {t.get('target_file','')}")
+    ed.begin_pin(abs(hash(tid + "_in")), ed.PinKind.input)
+    imgui.text("->")
+    ed.end_pin()
+    imgui.same_line()
+    ed.begin_pin(abs(hash(tid + "_out")), ed.PinKind.output)
+    imgui.text("->")
+    ed.end_pin()
+    ed.end_node()
+   for t in self.active_tickets:
+    tid = str(t.get('id', '??'))
     for dep in t.get('depends_on', []):
-     if dep not in children_map: children_map[dep] = []
-     children_map[dep].append(str(t.get('id') or ''))
-     # Roots are those whose depends_on elements are NOT in all_ids
-   roots = []
-   for t in self.active_tickets:
-    deps = t.get('depends_on', [])
-    has_local_dep = any(d in all_ids for d in deps)
-    if not has_local_dep:
-     roots.append(t)
-   rendered: set[str] = set()
-   for root in roots:
-    self._render_ticket_dag_node(root, tickets_by_id, children_map, rendered)
-    # 5. Add Ticket Form
+     ed.link(abs(hash(dep + "_" + tid)), abs(hash(dep + "_out")), abs(hash(tid + "_in")))
+   ed.end()
+   ed.set_current_editor(None)
+   # 5. Add Ticket Form
    imgui.separator()
    if imgui.button("Add Ticket"):
     self._show_add_ticket_form = not self._show_add_ticket_form
@@ -1602,6 +1627,25 @@ class App:
   else:
    imgui.text_disabled("No active MMA track.")
 
+  # 6. Edit Selected Ticket
+  if self.ui_selected_ticket_id:
+   imgui.separator()
+   imgui.text_colored(C_VAL, f"Editing: {self.ui_selected_ticket_id}")
+   ticket = next((t for t in self.active_tickets if str(t.get('id', '')) == self.ui_selected_ticket_id), None)
+   if ticket:
+    imgui.text(f"Status: {ticket.get('status', 'todo')}")
+    imgui.text(f"Target: {ticket.get('target_file', '')}")
+    deps = ticket.get('depends_on', [])
+    imgui.text(f"Depends on: {', '.join(deps)}")
+    if imgui.button(f"Mark Complete##{self.ui_selected_ticket_id}"):
+     ticket['status'] = 'done'
+     self._push_mma_state_update()
+    imgui.same_line()
+    if imgui.button(f"Delete##{self.ui_selected_ticket_id}"):
+     self.active_tickets = [t for t in self.active_tickets if str(t.get('id', '')) != self.ui_selected_ticket_id]
+     self.ui_selected_ticket_id = None
+     self._push_mma_state_update()
+
  def _render_tier_stream_panel(self, tier_key: str, stream_key: str | None) -> None:
   if stream_key is not None:
    content = self.mma_streams.get(stream_key, "")
@@ -1632,79 +1676,6 @@ class App:
       pass
      imgui.end_child()
 
- def _render_ticket_dag_node(self, ticket: dict[str, Any], tickets_by_id: dict[str, Any], children_map: dict[str, list[str]], rendered: set[str]) -> None:
-  tid = ticket.get('id', '??')
-  is_duplicate = tid in rendered
-  if not is_duplicate:
-   rendered.add(tid)
-  target = ticket.get('target_file', 'general')
-  status = ticket.get('status', 'pending').upper()
-  status_color = vec4(178, 178, 178)
-  if status == 'RUNNING':
-   status_color = vec4(255, 255, 0)
-  elif status == 'COMPLETE':
-   status_color = vec4(0, 255, 0)
-  elif status in ['BLOCKED', 'ERROR']:
-   status_color = vec4(255, 0, 0)
-  elif status == 'PAUSED':
-   status_color = vec4(255, 165, 0)
-  p_min = imgui.get_cursor_screen_pos()
-  p_max = imgui.ImVec2(p_min.x + 4, p_min.y + imgui.get_text_line_height())
-  imgui.get_window_draw_list().add_rect_filled(p_min, p_max, imgui.get_color_u32(status_color))
-  imgui.set_cursor_screen_pos(imgui.ImVec2(p_min.x + 8, p_min.y))
-  flags = imgui.TreeNodeFlags_.open_on_arrow | imgui.TreeNodeFlags_.open_on_double_click | imgui.TreeNodeFlags_.default_open
-  children = children_map.get(tid, [])
-  if not children or is_duplicate:
-   flags |= imgui.TreeNodeFlags_.leaf
-  node_open = imgui.tree_node_ex(f"##{tid}", flags)
-  if imgui.is_item_hovered():
-   imgui.begin_tooltip()
-   imgui.text_colored(C_KEY, f"ID: {tid}")
-   imgui.text_colored(C_LBL, f"Target: {target}")
-   imgui.text_colored(C_LBL, "Description:")
-   imgui.same_line()
-   imgui.text_wrapped(ticket.get('description', 'N/A'))
-   deps = ticket.get('depends_on', [])
-   if deps:
-    imgui.text_colored(C_LBL, f"Depends on: {', '.join(deps)}")
-   stream_key = f"Tier 3: {tid}"
-   if stream_key in self.mma_streams:
-    imgui.separator()
-    imgui.text_colored(C_KEY, "Worker Stream:")
-    imgui.text_wrapped(self.mma_streams[stream_key])
-   imgui.end_tooltip()
-  imgui.same_line()
-  imgui.text_colored(C_KEY, tid)
-  imgui.same_line(150)
-  imgui.text_disabled(str(target))
-  imgui.same_line(400)
-  imgui.text_colored(status_color, status)
-  imgui.same_line(500)
-  if imgui.button(f"Retry##{tid}"):
-   self._cb_ticket_retry(tid)
-  imgui.same_line()
-  if imgui.button(f"Skip##{tid}"):
-   self._cb_ticket_skip(tid)
-  if status in ['TODO', 'BLOCKED']:
-   imgui.same_line()
-   if imgui.button(f"Delete##{tid}"):
-    self.active_tickets = [t for t in self.active_tickets if t.get('id') != tid]
-    for t in self.active_tickets:
-     deps = t.get('depends_on', [])
-     if tid in deps:
-      t['depends_on'] = [d for d in deps if d != tid]
-    self._push_mma_state_update()
-  if is_duplicate:
-   imgui.same_line()
-   imgui.text_disabled("(shown above)")
-  if node_open and not is_duplicate:
-   for child_id in children:
-    child = tickets_by_id.get(child_id)
-    if child:
-     self._render_ticket_dag_node(child, tickets_by_id, children_map, rendered)
-   imgui.tree_pop()
-
- def _render_comms_history_panel(self) -> None:
   imgui.text_colored(vec4(200, 220, 160), f"Status: {self.ai_status}")
   imgui.same_line()
   if imgui.button("Clear##comms"):