Update documentation to explain Search and Filtering relationships

[coderabbitai]

Description

We need to update our documentation to clarify the relationships between:

• Search and Filtering functionality
• KQL filtering and Log level filtering

This will help users better understand how these features work together and improve the overall user experience.

Context

This documentation update was identified as a relatively low priority but important item during the review of PR #371, which added KQL query support for filtering structured IR log events.

Proposed Changes

• Update the existing log level filtering section, or
• Create a new documentation section
• Explain how Search and Filtering relate to each other
• Clarify the relationship between KQL filtering and Log level filtering

References

• PR: feat: Add KQL query support for filtering structured IR log events (fixes #277). #371
• Original comment: feat: Add KQL query support for filtering structured IR log events (fixes #277). #371 (comment)

Priority

Low priority but important for user experience.