feat(viz): helpers puros para dod_evidence_panel (issue 0117)

DodItem/DodEvidence/DodPanelState + count_status/find_evidence/
status_icon_id/status_color_token. Sin ImGui — testeable en aislamiento.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

cpp/functions/viz/dod_evidence_panel_helpers.h

@@ -0,0 +1,75 @@
+#pragma once
+
+// dod_evidence_panel_helpers — logica pura, sin ImGui.
+// Tests (cpp/tests/test_dod_evidence_panel.cpp) linkan SOLO este archivo
+// para validar conteos, lookup y mapeo de status -> icon/color.
+
+#include <string>
+#include <vector>
+#include <functional>
+#include <cstdint>
+
+namespace fn_viz {
+
+struct DodItem {
+    std::string id;
+    std::string kind;        // screenshot|log|url|cmd
+    std::string expected;
+    bool        required = true;
+    std::string status;      // pending|done|validated|failed
+};
+
+struct DodEvidence {
+    std::string item_id;
+    std::string kind;
+    std::string payload_path;  // screenshot/log
+    std::string payload_url;   // url
+    std::string payload_text;  // cmd output
+    int64_t     attached_at = 0;
+    bool        validated = false;
+    std::string validated_by;
+};
+
+struct DodPanelState {
+    std::vector<DodItem>     items;
+    std::vector<DodEvidence> evidences;
+    std::string run_id;
+    std::function<void(const std::string& item_id)> on_validate;
+    std::function<void(const std::string& item_id)> on_reject;
+};
+
+namespace dod_panel {
+
+struct StatusCounts {
+    int total = 0;
+    int pending = 0;
+    int done = 0;
+    int validated = 0;
+    int failed = 0;
+    int missing_required = 0;  // required + no evidence + status != done/validated
+};
+
+// Cuenta items por status. Si un item required NO tiene evidence y su status
+// no es done/validated, suma missing_required.
+StatusCounts count_status(const DodPanelState& state);
+
+// Busca la primera evidence cuyo item_id == item_id. nullptr si no existe.
+const DodEvidence* find_evidence(const DodPanelState& state, const std::string& item_id);
+
+// Status -> icon key (uso interno; en render se mapea a TI_*).
+//   pending   -> "circle-dashed"
+//   done      -> "circle-dot"
+//   validated -> "circle-check"
+//   failed    -> "circle-x"
+//   otro      -> "circle-dashed"
+std::string status_icon_id(const std::string& status);
+
+// Status -> color token.
+//   0 = neutral (pending / desconocido)
+//   1 = info    (done)
+//   2 = success (validated)
+//   3 = danger  (failed)
+int status_color_token(const std::string& status);
+
+}  // namespace dod_panel
+}  // namespace fn_viz