Add progress tracking and memory estimation for JDBC module

This commit introduces progress tracking functionality for the JDBC module, including both simple and detailed modes configurable via system properties. Added new tests, configuration class (`JdbcConfig`), and memory estimation utilities to ensure efficient handling of large datasets.

Author: zaleslaw

dataframe-jdbc/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/JdbcConfig.kt

@@ -0,0 +1,68 @@
+package org.jetbrains.kotlinx.dataframe.io
+
+/**
+ * Internal configuration for JDBC module behavior.
+ * Controlled via system properties or environment variables.
+ *
+ * Example usage:
+ * ```kotlin
+ * // Enable progress with detailed statistics
+ * System.setProperty("dataframe.jdbc.progress", "true")
+ * System.setProperty("dataframe.jdbc.progress.detailed", "true")
+ *
+ * // Or via environment variables
+ * export DATAFRAME_JDBC_PROGRESS=true
+ * export DATAFRAME_JDBC_PROGRESS_DETAILED=true
+ * ```
+ */
+internal object JdbcConfig {
+    /**
+     * Enable progress logging during data loading.
+     *
+     * When `true`, enables DEBUG-level progress messages and memory estimates.
+     * When `false` (default), only respects logger level (e.g., DEBUG).
+     *
+     * System property: `-Ddataframe.jdbc.progress=true`
+     * Environment variable: `DATAFRAME_JDBC_PROGRESS=true`
+     * Default: `false`
+     */
+    @JvmStatic
+    val PROGRESS_ENABLED: Boolean by lazy {
+        System.getProperty("dataframe.jdbc.progress")?.toBoolean()
+            ?: System.getenv("DATAFRAME_JDBC_PROGRESS")?.toBoolean()
+            ?: false
+    }
+
+    /**
+     * Enable detailed progress logging with statistics.
+     *
+     * When `true`: Shows row count, percentage, speed (rows/sec), memory usage
+     * When `false`: Shows only basic "Loaded X rows" messages
+     *
+     * Only takes effect when progress is enabled.
+     *
+     * System property: `-Ddataframe.jdbc.progress.detailed=true`
+     * Environment variable: `DATAFRAME_JDBC_PROGRESS_DETAILED=true`
+     * Default: `true`
+     */
+    @JvmStatic
+    val PROGRESS_DETAILED: Boolean by lazy {
+        System.getProperty("dataframe.jdbc.progress.detailed")?.toBoolean()
+            ?: System.getenv("DATAFRAME_JDBC_PROGRESS_DETAILED")?.toBoolean()
+            ?: true
+    }
+
+    /**
+     * Report progress every N rows.
+     *
+     * System property: `-Ddataframe.jdbc.progress.interval=5000`
+     * Environment variable: `DATAFRAME_JDBC_PROGRESS_INTERVAL=5000`
+     * Default: `1000`
+     */
+    @JvmStatic
+    val PROGRESS_INTERVAL: Int by lazy {
+        System.getProperty("dataframe.jdbc.progress.interval")?.toIntOrNull()
+            ?: System.getenv("DATAFRAME_JDBC_PROGRESS_INTERVAL")?.toIntOrNull()
+            ?: 1000
+    }
+}