Update max context items in general settings
Follow up to:
#3573715
## Problem/motivation
"Increase Max context items to inject default from 5 to 10. The current default is conservative for a system designed around bundling small, focused Context Items. A single text-editing task could reasonably want Brand Guidelines, Tone & Voice, Vocabulary, Content Structure, and Page Building rules to all apply, which already hits 5. Defaulting to 10 gives breathing room without being unbounded."
## Solution
Update default to 10 and max to 20.
## Tasks
- Update code
- Review and test
## AI usage disclosures
- [ ] AI assisted issue
- [x] AI assisted code
- [ ] AI generated code
issue