[Initial commit] Add telemetry log levels (#1032)

## Description
- This is the first PR to introduce log levels to telemetry. 

## Testing
- Unit tests added

## Additional Notes to the Reviewer
- In subsequent PRs, we will be incorporating logLevels in telemetry
push too.
- Internal doc :
https://docs.google.com/document/d/1EmsW4jYMtpvjlLovyRQsOwqIBAN-MAcOZKAS0Bm0c7Q/edit?tab=t.0

 NO_CHANGELOG=true
OVERRIDE_FREEZE=true
(Note that the release is already made, I will remove the freeze in my
next PR)

Author: samikshya-db

src/main/java/com/databricks/jdbc/api/impl/DatabricksConnectionContext.java

@@ -1071,4 +1071,10 @@ public boolean isBatchedInsertsEnabled() {
   public boolean getIgnoreTransactions() {
     return getParameter(DatabricksJdbcUrlParams.IGNORE_TRANSACTIONS, "0").equals("1");
   }
+
+  @Override
+  public TelemetryLogLevel getTelemetryLogLevel() {
+    return TelemetryLogLevel.parse(
+        getParameter(DatabricksJdbcUrlParams.TELEMETRY_LOG_LEVEL), TelemetryLogLevel.DEBUG);
+  }
 }

src/main/java/com/databricks/jdbc/api/internal/IDatabricksConnectionContext.java

@@ -74,6 +74,8 @@ public interface IDatabricksConnectionContext {
 
   LogLevel getLogLevel();
 
+  TelemetryLogLevel getTelemetryLogLevel();
+
   String getLogPathString();
 
   int getLogFileSize();

src/main/java/com/databricks/jdbc/common/DatabricksJdbcUrlParams.java

@@ -5,6 +5,7 @@
 /** Enum to hold all the Databricks JDBC URL parameters. */
 public enum DatabricksJdbcUrlParams {
   LOG_LEVEL("loglevel", "Log level for debugging"),
+  TELEMETRY_LOG_LEVEL("telemetryLogLevel", "Log level for telemetry logs", "DEBUG"),
   LOG_PATH("logpath", "Path to the log file"),
   LOG_FILE_SIZE("LogFileSize", "Maximum size of the log file", "10"), // 10 MB
   LOG_FILE_COUNT("LogFileCount", "Number of log files to retain", "10"),

src/main/java/com/databricks/jdbc/common/TelemetryLogLevel.java

@@ -0,0 +1,78 @@
+package com.databricks.jdbc.common;
+
+/**
+ * Telemetry log verbosity for structured driver events; independent of {@link LogLevel} and set via
+ * {@code telemetryLogLevel} (see {@link DatabricksJdbcUrlParams#TELEMETRY_LOG_LEVEL}).
+ */
+public enum TelemetryLogLevel {
+  /** Disable telemetry logging. */
+  OFF(0),
+
+  /** Unrecoverable conditions that abort processing. */
+  FATAL(1),
+
+  /** Errors that fail an operation but do not crash the process. */
+  ERROR(2),
+
+  /** Potential issues without interrupting normal flow. */
+  WARN(3),
+
+  /** High-level normal activity. */
+  INFO(4),
+
+  /** Detailed diagnostics for troubleshooting. */
+  DEBUG(5),
+
+  /** Maximum verbosity including internal timings and state. */
+  TRACE(6);
+
+  private final int code;
+
+  TelemetryLogLevel(int code) {
+    this.code = code;
+  }
+
+  /** Returns the integer code for this level. */
+  public int toInt() {
+    return code;
+  }
+
+  /** Parses a telemetry level from its integer code. Defaults to DEBUG for unknown codes. */
+  public static TelemetryLogLevel fromInt(int code) {
+    switch (code) {
+      case 0:
+        return OFF;
+      case 1:
+        return FATAL;
+      case 2:
+        return ERROR;
+      case 3:
+        return WARN;
+      case 4:
+        return INFO;
+      case 5:
+        return DEBUG;
+      case 6:
+        return TRACE;
+      default:
+        return DEBUG;
+    }
+  }
+
+  /** Parses from string accepting either integer codes or names; falls back to defaultLevel. */
+  public static TelemetryLogLevel parse(String value, TelemetryLogLevel defaultLevel) {
+    if (value == null) return defaultLevel;
+    String v = value.trim();
+    if (v.isEmpty()) return defaultLevel;
+    try {
+      return fromInt(Integer.parseInt(v));
+    } catch (NumberFormatException ignored) {
+      // not an integer
+    }
+    try {
+      return TelemetryLogLevel.valueOf(v.toUpperCase());
+    } catch (IllegalArgumentException ignored) {
+      return defaultLevel;
+    }
+  }
+}

src/test/java/com/databricks/jdbc/api/impl/DatabricksConnectionContextTest.java

@@ -22,6 +22,8 @@
 import java.util.Properties;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 class DatabricksConnectionContextTest {
 
@@ -505,6 +507,29 @@ void testLogLevels() {
     assertEquals(getLogLevel(6), LogLevel.TRACE);
   }
 
+  @ParameterizedTest
+  @CsvSource(
+      value = {
+        "<NULL>, DEBUG",
+        "'', DEBUG",
+        "6, TRACE",
+        "0, OFF",
+        "'  trace  ', TRACE",
+        "nope, DEBUG"
+      },
+      nullValues = "<NULL>")
+  void testTelemetryLogLevelParameterized(String input, TelemetryLogLevel expected)
+      throws DatabricksSQLException {
+    String baseUrl = TestConstants.VALID_URL_1;
+    Properties props = new Properties();
+    if (input != null) {
+      props.setProperty("telemetryLogLevel", input);
+    }
+    DatabricksConnectionContext ctx =
+        (DatabricksConnectionContext) DatabricksConnectionContext.parse(baseUrl, props);
+    assertEquals(expected, ctx.getTelemetryLogLevel());
+  }
+
   @Test
   public void testGetOAuth2RedirectUrlPorts() throws DatabricksSQLException {
     // Test default value