fix: build errors — nlohmann include path, fn_log printf style, crypt32 link

- Fix nlohmann include: 'vendor/nlohmann/json.hpp' -> 'nlohmann/json.hpp'
  (cpp/vendor is in include path, no double-vendor prefix needed)
- Fix fn_log API: log_info/log_warn/log_error (not info/warn/error)
- Fix format strings: {} -> %s (logger uses printf-style, not fmtlib)
- CMakeLists: add crypt32 link for Windows DPAPI (MinGW needs explicit link,
  #pragma comment(lib) only works with MSVC)
- Build: exit 0, exe 22MB, .rsrc section present (icon embedded)

Issue: 0129
Co-Authored-By: fn-orquestador <noreply@fn-registry.local>

CMakeLists.txt

@@ -19,4 +19,6 @@ endif()
 
 if(WIN32)
     set_target_properties(agents_dashboard PROPERTIES WIN32_EXECUTABLE TRUE)
+    # secret_store.cpp uses CryptProtectData / CryptUnprotectData (crypt32)
+    target_link_libraries(agents_dashboard PRIVATE crypt32)
 endif()

main.cpp

@@ -19,7 +19,7 @@
 #include "core/http_get_json.h"
 #include "core/sse_client.h"
 #include "infra/secret_store.h"
-#include "vendor/nlohmann/json.hpp"
+#include "nlohmann/json.hpp"
 
 // SQLite (vendored via fn_framework)
 #include <sqlite3.h>
@@ -127,7 +127,7 @@ static bool db_open(AppState& s) {
     if (s.db) return true;
     const char* path = fn::local_path("agents_dashboard.db");
     if (sqlite3_open(path, &s.db) != SQLITE_OK) {
-        fn_log::error("[db] open failed: {}", sqlite3_errmsg(s.db));
+        fn_log::log_error("[db] open failed: %s", sqlite3_errmsg(s.db));
         return false;
     }
     // Apply migrations embedded in source
@@ -153,7 +153,7 @@ static bool db_open(AppState& s) {
     for (const char** m = migrations; *m; ++m) {
         char* errmsg = nullptr;
         if (sqlite3_exec(s.db, *m, nullptr, nullptr, &errmsg) != SQLITE_OK) {
-            fn_log::warn("[db] migration warning: {}", errmsg ? errmsg : "?");
+            fn_log::log_warn("[db] migration warning: %s", errmsg ? errmsg : "?");
             sqlite3_free(errmsg);
         }
     }
@@ -164,7 +164,7 @@ static void db_save_connection(AppState& s) {
     if (!s.db) return;
     auto blob = fn_secret::encrypt(s.apikey_buf);
     if (blob.empty()) {
-        fn_log::warn("[db] encrypt failed, not saving apikey");
+        fn_log::log_warn("[db] encrypt failed, not saving apikey");
         return;
     }
     // Upsert connection id=1
@@ -181,7 +181,7 @@ static void db_save_connection(AppState& s) {
     sqlite3_bind_blob(stmt, 2, blob.data(), (int)blob.size(), SQLITE_TRANSIENT);
     sqlite3_step(stmt);
     sqlite3_finalize(stmt);
-    fn_log::info("[db] connection saved");
+    fn_log::log_info("[db] connection saved");
 }
 
 static void db_load_connection(AppState& s) {
@@ -200,7 +200,7 @@ static void db_load_connection(AppState& s) {
             std::string key = fn_secret::decrypt(b);
             if (!key.empty()) {
                 snprintf(s.apikey_buf, sizeof(s.apikey_buf), "%s", key.c_str());
-                fn_log::info("[db] credentials loaded");
+                fn_log::log_info("[db] credentials loaded");
             }
         }
     }
@@ -288,7 +288,7 @@ static void agent_action(AppState& s, const std::string& agent_id,
         } else {
             fb = "[" + action + " " + agent_id + "] HTTP " + std::to_string(res.status);
         }
-        fn_log::info("{}", fb.c_str());
+        fn_log::log_info("%s", fb.c_str());
         {
             std::lock_guard<std::mutex> lk(s.action_mu);
             s.action_feedback = fb;
@@ -358,7 +358,7 @@ static void start_status_sse(AppState& s) {
 static bool g_self_test = false;
 
 static bool run_self_test() {
-    fn_log::info("[self-test] checking subsystems...");
+    fn_log::log_info("[self-test] checking subsystems...");
 
     // 1. DB
     if (!db_open(g_state)) {
@@ -460,7 +460,7 @@ static void draw_connection_panel(AppState& s) {
     if (ImGui::Button(TI_PLUG " Test Connection")) {
         s.connect_error.clear();
         s.connected = false;
-        fn_log::info("[connect] testing {}...", s.base_url);
+        fn_log::log_info("[connect] testing %s...", s.base_url);
         // Synchronous health check (small timeout)
         fn_http::Request req;
         req.method       = "GET";
@@ -470,13 +470,13 @@ static void draw_connection_panel(AppState& s) {
         auto res = fn_http::request(req);
         if (!res.error.empty()) {
             s.connect_error = "Transport error: " + res.error;
-            fn_log::warn("[connect] {}", s.connect_error.c_str());
+            fn_log::log_warn("[connect] %s", s.connect_error.c_str());
         } else if (res.status != 200) {
             s.connect_error = "HTTP " + std::to_string(res.status) + " from /health";
-            fn_log::warn("[connect] {}", s.connect_error.c_str());
+            fn_log::log_warn("[connect] %s", s.connect_error.c_str());
         } else {
             s.connected = true;
-            fn_log::info("[connect] OK");
+            fn_log::log_info("[connect] OK");
             db_save_connection(s);
             // Start SSEs
             start_status_sse(s);