MM2: Implement Fault Tolerance for Log Truncation and Topic Reset

[prince286]

This Pull Request implements two key fault tolerance features within MirrorMaker's MirrorSourceTask to enhance data integrity in mission-critical deployments.

The changes address the risk of silent data loss (truncation) and service disruption (topic reset).

1. Log Truncation Detection (Fail-Fast)

Problem: Kafka's retention policies can delete log segments, causing MM2's consumer to lose its expected offset and silently skip data.
Solution (in MirrorSourceTask.java):
An in-memory map tracks the last processed offset for each partition. If the newly polled offset is greater than the last processed offset + 1, a data gap is confirmed.

• Action: Throws a ConnectException with a CRITICAL log message, forcing a Fail-Fast stop and preventing further silent data loss.

2. Graceful Topic Reset Handling (Auto-Recovery)

Problem: Deleting and recreating the source topic resets its offset to 0. MM2's stored offset is now invalid.
Solution (in MirrorSourceTask.java):
The logic detects if the newly polled offset is less than the last processed offset (indicating a log reset/topic recreation).

• Action: Logs an AUTO-RECOVERED event but does not throw an exception. The consumer automatically resets to the earliest offset (0) based on Connect's default behavior, allowing replication to resume immediately.

3. Environment Fix (MirrorUtils.java)

Problem: Single-node Connect deployments fail due to Kafka 4.0.0's strict default replication factor of 3 for internal topics.
Solution (in MirrorUtils.java):
The createCompactedTopic method is modified to explicitly set replicationFactor = 1, ensuring compatibility with single-broker testing environments.

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