feat(bigquery-jdbc): add EnableTimestampPicos connection property and its plumbing

[keshavdandeva]

b/544843125

This PR introduces the EnableTimestampPicos connection property to configure 12-digit picosecond precision for BigQuery TIMESTAMP(12) data, establishing the configuration foundation across the driver pipeline.

Key Changes

• Configuration & URL Plumbing:
  • Defined ENABLE_TIMESTAMP_PICOS_PROPERTY_NAME = "EnableTimestampPicos" (default: false) in BigQueryJdbcUrlUtility.java
  • Added standard getters/setters in DataSource.java and registered the setter in PROPERTY_SETTERS via convertIntToBoolean (supporting 1, 0, true, false)
  • Propagated the flag through BigQueryConnection.java (registered in SAFE_TO_LOG_PROPERTIES) and into immutable BigQuerySettings.java
• Documentation:
  • Documented the configuration property and precision behavior in docs/USER_GUIDE.md

Testing

• BigQueryJdbcUrlUtilityTest.java: Verified parsing of EnableTimestampPicos (1 and 0).
• BigQueryConnectionTest.java: Verified default (false) and URL-configured (true) states.

[gemini-code-assist]

Code Review

This pull request introduces a new connection property, EnableTimestampPicos, to support 12-digit picosecond precision for TIMESTAMP(12) data types in the BigQuery JDBC driver. The feedback highlights a critical issue in BigQueryStatement.java where catching any BigQueryException when EnableTimestampPicos is enabled and Legacy SQL is used will mask all other unrelated errors (such as syntax errors or permission issues). It is recommended to inspect the exception details to ensure the error is actually related to timestamp precision before throwing the compatibility exception.

[keshavdandeva]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces a new connection property, EnableTimestampPicos, to enable 12-digit picosecond precision for TIMESTAMP(12) data types in the BigQuery JDBC driver. The changes span documentation, configuration utilities, connection settings, and statements, along with corresponding unit tests. Feedback on the changes includes a request to implement the missing error translation logic and tests for Legacy SQL backend failures as described in the PR description, and a suggestion to use Boolean.TRUE.equals() when retrieving the property from the data source to prevent a potential NullPointerException from automatic unboxing.