feat: Add multi-statement transaction support

[jayantsing-db]

What type of PR is this?

• Refactor
• Feature
• Bug Fix
• Other

Description

Implement PEP 249-compliant transaction control with extensions for manual commit/rollback operations. This enables atomic multi-table operations with REPEATABLE_READ isolation semantics.

Core API additions:

• connection.autocommit property for enabling/disabling auto-commit mode
• connection.commit() to commit active transactions
• connection.rollback() to rollback active transactions
• connection.get_transaction_isolation() returns current isolation level
• connection.set_transaction_isolation() validates isolation level
• TransactionError exception for transaction-specific failures

Implementation details:

• Added autocommit state caching in Session with optional server query
• Added TRANSACTION_ISOLATION_LEVEL_REPEATABLE_READ constant
• All transaction operations include proper error handling and telemetry
• Supports fetch_autocommit_from_server connection parameter

Testing:

• Unit tests covering all transaction methods and error scenarios
• e2e integration tests validating transaction behavior including multi-table atomicity, sequential transactions, and isolation semantics

Documentation:

• Comprehensive TRANSACTIONS.md guide with examples and best practices
• Updated README.md with basic usage and reference to detailed docs

Requires MST-enabled Databricks SQL warehouse and Delta tables with 'delta.feature.catalogOwned-preview' table property.

How is this tested?

• Unit tests
• E2E Tests
• Manually
• N/A

Related Tickets & Documents

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[github-actions]

Thanks for your contribution! To satisfy the DCO policy in our contributing guide every commit message must include a sign-off message. One or more of your commits is missing this message. You can reword previous commit messages with an interactive rebase (git rebase -i main).

[github-actions]

Thanks for your contribution! To satisfy the DCO policy in our contributing guide every commit message must include a sign-off message. One or more of your commits is missing this message. You can reword previous commit messages with an interactive rebase (git rebase -i main).