feat: initial scaffold kanban_cpp v0.1.0

C++ ImGui kanban for steering LLM agents. Six panels (Board, Calendar,
Dashboard, Agent runs, Worktrees, DoD inspector) wired to registry
functions http_request, kpi_card, sparkline, agent_runs_timeline,
dod_evidence_panel. Backend Go on :8403 (independent operations.db from
kanban_web).

panel_dod.cpp

@@ -0,0 +1,43 @@
+// panel_dod.cpp — DoD evidence inspector wrapping the registry panel.
+//
+// MVP: uses a synthetic in-memory DodPanelState so the panel renders without
+// the agent_runner_api wired up. When that API exposes /api/dod_items +
+// /api/dod_evidences endpoints, this will fetch them like panel_agent_runs.
+#include "panels.h"
+#include "core/icons_tabler.h"
+#include "viz/dod_evidence_panel.h"
+
+#include <imgui.h>
+
+namespace kanban_cpp {
+
+namespace {
+
+fn_viz::DodPanelState& state_singleton() {
+    static fn_viz::DodPanelState st;
+    static bool inited = false;
+    if (!inited) {
+        st.run_id = "(none)";
+        // Empty until wired to backend. Helpers count zeros gracefully.
+        inited = true;
+    }
+    return st;
+}
+
+} // namespace
+
+void draw_dod(AppState& /*s*/, bool* p_open) {
+    if (!ImGui::Begin(TI_LIST_CHECK " DoD inspector", p_open)) {
+        ImGui::End();
+        return;
+    }
+
+    auto& st = state_singleton();
+    ImGui::TextDisabled("run_id: %s   (TODO: wire to agent_runner_api)", st.run_id.c_str());
+    ImGui::Separator();
+    fn_viz::render_dod_evidence_panel(st);
+
+    ImGui::End();
+}
+
+} // namespace kanban_cpp