feat: add TestEnv with named accounts, log transform, and env-var logging

TestEnv wraps Env with:
- account("name"): auto-registers r-address → Account(name) in logs
- TESTENV_LOGGING env var: "HooksTrace=trace,View=debug" sets
  per-partition log levels without code changes

src/test/jtx/TestEnv.h

@@ -0,0 +1,134 @@
+#ifndef TEST_JTX_TESTENV_H_INCLUDED
+#define TEST_JTX_TESTENV_H_INCLUDED
+
+#include <test/jtx/Env.h>
+#include <xrpl/basics/Log.h>
+#include <xrpl/protocol/AccountID.h>
+#include <cstdlib>
+#include <cstring>
+#include <map>
+#include <string>
+#include <sstream>
+
+namespace ripple {
+namespace test {
+namespace jtx {
+
+/**
+ * TestEnv wraps Env with:
+ *   - Named account registry: env.account("alice")
+ *   - Auto log transform: replaces r-addresses with Account(name) in log output
+ *   - Env-var driven per-partition log levels via TESTENV_LOGGING
+ *
+ * Usage:
+ *   TestEnv env{suite, features};
+ *   auto const& alice = env.account("alice");
+ *   auto const& bob = env.account("bob");
+ *   env.fund(XRP(10000), alice, bob);
+ *   // Logs now show Account(alice), Account(bob) instead of r-addresses
+ *
+ * Log levels via env var:
+ *   TESTENV_LOGGING="HooksTrace=trace,View=debug"
+ *
+ * Valid levels: trace, debug, info, warning, error, fatal
+ */
+class TestEnv : public Env
+{
+    std::map<std::string, Account> accounts_;
+
+public:
+    TestEnv(
+        beast::unit_test::suite& suite,
+        FeatureBitset features)
+        : Env(suite, features)
+    {
+        installTransform();
+        applyLoggingEnvVar();
+    }
+
+    TestEnv(
+        beast::unit_test::suite& suite,
+        std::unique_ptr<Config> config,
+        FeatureBitset features,
+        std::unique_ptr<Logs> logs = nullptr,
+        beast::severities::Severity thresh = beast::severities::kError)
+        : Env(suite, std::move(config), features, std::move(logs), thresh)
+    {
+        installTransform();
+        applyLoggingEnvVar();
+    }
+
+    ~TestEnv()
+    {
+        app().logs().setTransform(nullptr);
+    }
+
+    /// Get or create a named account.
+    /// First call creates the Account; subsequent calls return the same one.
+    Account const&
+    account(std::string const& name)
+    {
+        auto [it, inserted] = accounts_.try_emplace(name, name);
+        return it->second;
+    }
+
+private:
+    static beast::severities::Severity
+    parseSeverity(std::string const& s)
+    {
+        if (s == "trace")   return beast::severities::kTrace;
+        if (s == "debug")   return beast::severities::kDebug;
+        if (s == "info")    return beast::severities::kInfo;
+        if (s == "warning") return beast::severities::kWarning;
+        if (s == "error")   return beast::severities::kError;
+        if (s == "fatal")   return beast::severities::kFatal;
+        return beast::severities::kError;
+    }
+
+    void
+    applyLoggingEnvVar()
+    {
+        // Parse TESTENV_LOGGING="Partition1=level,Partition2=level"
+        auto const* envVal = std::getenv("TESTENV_LOGGING");
+        if (!envVal || !envVal[0])
+            return;
+
+        std::istringstream ss(envVal);
+        std::string pair;
+        while (std::getline(ss, pair, ','))
+        {
+            auto eq = pair.find('=');
+            if (eq == std::string::npos)
+                continue;
+            auto partition = pair.substr(0, eq);
+            auto level = pair.substr(eq + 1);
+            app().logs().get(partition).threshold(parseSeverity(level));
+        }
+    }
+
+    void
+    installTransform()
+    {
+        app().logs().setTransform([this](std::string const& text) {
+            std::string out = text;
+            for (auto const& [name, acc] : accounts_)
+            {
+                auto raddr = toBase58(acc.id());
+                std::string::size_type pos = 0;
+                std::string replacement = "Account(" + name + ")";
+                while ((pos = out.find(raddr, pos)) != std::string::npos)
+                {
+                    out.replace(pos, raddr.size(), replacement);
+                    pos += replacement.size();
+                }
+            }
+            return out;
+        });
+    }
+};
+
+}  // namespace jtx
+}  // namespace test
+}  // namespace ripple
+
+#endif