feat(coderabbit): add docs-staleness check for src/ changes

[alexeyv]

Summary

• Adds a path_instructions entry for src/** that tells CodeRabbit to flag when documentation under docs/ may need updating whenever source files are modified
• Covers new features, changed behavior, renamed concepts, altered CLI flags, and modified configuration options
• Stacks additively with existing path-specific instructions (skills, workflows, tasks, agents)

Test plan

• Open a PR that modifies a file under src/ and verify CodeRabbit includes the docs-staleness check in its review
• Open a PR that only modifies files outside src/ and verify the instruction does not fire

🤖 Generated with Claude Code

[augmentcode]

🤖 Augment PR Summary

Summary: Adds a CodeRabbit path_instructions rule for src/** to flag potentially stale documentation under docs/ when source files change.
Why: Encourages doc updates alongside new/changed behavior, renamed concepts, CLI flags, and configuration options.

_{🤖 Was this summary useful? React with 👍 or 👎}

[augmentcode]

Review completed. No suggestions at this time.

Comment augment review to trigger a new review at any time.