Add 'Quiet hours' user preference applied to push and SR announcements (v4 patch)

[greatest0fallt1me]

Description

This is a ui/ux issue for the GrantFox campaign. Honor user-set quiet hours for non-critical announcements.

Requirements and Context

• Implement per the description
• Add focused tests for the change
• Document any API/visible changes
• Adhere to repo's lint and code style
• Must be secure, tested, and documented

Suggested Execution

1. Fork the repo and create a branch

   git checkout -b feature/quiet-hours

2. Implement changes
3. Test and commit

Example commit message

feat: quiet hours preference

Acceptance Criteria

• Implementation matches the description
• Tests added and passing
• Code review approved
• Docs updated

Guidelines

• Clear documentation and inline comments
• Timeframe: 96 hours

[jaynomyaro]

Hi! I came across this issue and would love to work on it. I have experience with similar tasks and I'm confident I can investigate, implement a clean solution, and thoroughly test it before submitting a PR. If the issue is still open, I would appreciate it if you could assign it to me. Thank you!

[Menjay7]

Hi! I’m a full-stack developer with a strong blockchain background. I’d love to handle this issue and can deliver a clean, reliable solution. Kindly assign it to me.