fix(settings): tolerate wrongly-typed values instead of quarantining

Several settings were read with json's value()/get<T>() helpers that
assume the stored type. A hand-edited settings file, or one re-saved
after an inf/NaN float was written back as JSON null, could therefore
hold a value of the wrong type and throw during load. The whole load is
wrapped so a throw quarantines the entire settings file to a
.corrupt- copy, meaning one bad field reset every unrelated setting.

- ui_opacity is accepted only when it is actually a number, and it is
  clamped to the same 0.3..1.0 range the setter enforces; the legacy
  reduced_transparency migration likewise runs only when that key is a
  boolean.
- A non-string name in a blocked chat conversation, and a non-string
  scope in a portfolio entry, now fall back to an empty string instead
  of throwing.

The file loads with the offending field defaulted, and the rest of the
settings survive.

Tests cover ui_opacity as a string/null/int/float/bool, a non-string
blocked-conversation name and portfolio scope, and the legacy
reduced_transparency migration, asserting no quarantine file is written.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_phase4.cpp

@@ -7918,6 +7918,47 @@ void testPortfolioScopeVisibility()
     std::error_code ec; fs::remove_all(dir, ec);
 }
 
+// Settings::load must tolerate wrongly-typed values without quarantining the whole file.
+void testSettingsLoadTypeTolerance()
+{
+    namespace fs = std::filesystem;
+    const fs::path dir = fs::temp_directory_path() / "dragonx_settings_type_tolerance_test";
+    std::error_code ec; fs::remove_all(dir, ec); fs::create_directories(dir, ec);
+    const std::string p = (dir / "settings.json").string();
+    auto writeAndLoad = [&](const std::string& json, dragonx::config::Settings& s) {
+        { std::ofstream o(p, std::ios::binary | std::ios::trunc); o << json; }
+        return s.load(p);
+    };
+    auto noQuarantine = [&]() {
+        for (const auto& de : fs::directory_iterator(dir, ec))
+            if (de.path().filename().string().find(".corrupt-") != std::string::npos) return false;
+        return true;
+    };
+    for (const char* bad : {"\"x\"", "null", "5", "0.01", "true"}) {
+        dragonx::config::Settings s;
+        const std::string js = std::string("{\"ui_opacity\":") + bad + ",\"chat_density\":1}";
+        EXPECT_TRUE(writeAndLoad(js, s));
+        EXPECT_TRUE(noQuarantine());
+        EXPECT_TRUE(s.getUIOpacity() >= 0.3f && s.getUIOpacity() <= 1.0f);
+    }
+    {
+        dragonx::config::Settings s;
+        EXPECT_TRUE(writeAndLoad(
+            "{\"blocked_chat_convs\":[{\"cid\":\"abc\",\"name\":7}],"
+            "\"portfolio_entries\":[{\"label\":\"L\",\"scope\":7}]}", s));
+        EXPECT_TRUE(noQuarantine());
+        EXPECT_EQ(s.blockedChatConversations().size(), static_cast<size_t>(1));
+        EXPECT_EQ(s.getPortfolioEntries().size(), static_cast<size_t>(1));
+        EXPECT_EQ(s.getPortfolioEntries()[0].scope, std::string());
+    }
+    {
+        dragonx::config::Settings s;
+        EXPECT_TRUE(writeAndLoad("{\"reduced_transparency\":true}", s));
+        EXPECT_NEAR(s.getUIOpacity(), 1.0f, 1e-6f);
+    }
+    fs::remove_all(dir, ec);
+}
+
 // Market price-series math (data/market_series.h) — minute-resampling + time-window bucketing
 // that feed the price chart and the portfolio-group sparklines.
 void testMarketSeries()
@@ -18669,6 +18710,7 @@ int main()
     testHushChatTransport();
     testHushChatShuffledReceive();
     testWalletFileProbe();
+    testSettingsLoadTypeTolerance();
     testAddressChecksumValidation();
     testPrivateKeyImportRecognition();
     testSeedPhraseHelpers();