Add docs, fix CSS selector, and add unit tests

[adrioui]

Summary

• Documentation: Add RisingWave to the supported execution engines list and document the --dotenv CLI option
• Bug Fix: Correct missing . prefix in CSS class selector for .react-flow__attribution
• Tests: Add comprehensive unit tests for conversions.py and hashing.py utilities

Changes

docs/integrations/overview.md

• Add RisingWave to the list of supported execution engines

docs/reference/cli.md

• Document the --dotenv CLI option for specifying custom .env file paths

web/client/src/library/components/graph/Graph.css

• Fix CSS selector react-flow__attribution → .react-flow__attribution

tests/utils/test_conversions.py (new)

• Unit tests for try_str_to_bool, ensure_bool, and make_serializable functions

tests/utils/test_hashing.py (new)

• Unit tests for crc32, md5, and hash_data functions

[CLAassistant]

All committers have signed the CLA.