[FE] Add form section for Stopping/Snoozing

Why are we doing this work

Users of GitLab Scheduled Pipeline Execution Policies need a way to temporarily pause pipeline executions during critical periods or maintenance windows. Otherwise, they must either disable the entire policy or manually manage schedules, which is inefficient and error-prone.

Relevant links

Non-functional requirements

• Documentation:
• Feature flag:
• Performance:
• Testing:

Implementation plan

• frontend add to schedule form to include the snooze option
• frontend allow for input for reason
• frontend allow for calendar for until

pipeline_execution_schedule_policy:
- name: "Scheduled PEP"
  enabled: true
  content:
    include:
    - project: path/to/project
      file: policy-ci.yml
  schedules:
  - type: daily
    start_time: "00:00"
    time_window:
      distribution: random
      value: 3600
    timezone: "America/New_York"
    snooze:
      reason: "Too many pipelines"
      until: "2025-06-26T16:27:00+00:00"

Verification steps