Endpoint to get a summary of runs for a given workflow instance

[anjujha]

Pull Request type

• Bugfix
• Feature
• Refactoring (no functional changes, no api changes)
• Build related changes (Please run ./gradlew build --write-locks to refresh dependencies)
• Other (please describe):

NOTE: Please remember to run ./gradlew spotlessApply to fix any format violations.

Changes in this PR

This PR adds support to get a summary of all the runs for a given workflow instance

1. Ran ./gradlew spotlessApply and ./gradlew build and verified it completes successfully
2. Verified locally by:
   • Launch maestro-server locally (./gradlew :maestro-server:bootRun)
   • Create sample workflow, trigger a run and restart it 5x
   • Tested GET /api/v3/workflows/{workflowId}/instances/{instanceId}/runs against an instance with 5 runs:
     1. ?first=10 returns all 5 runs in descending order (run 5 → 1), total_count=5, has_next_page=false
     2. ?first=2 returns runs [5, 4], has_next_page=true, has_previous_page=false
     3. ?first=2&cursor=4 returns runs [3, 2], has_next_page=true, has_previous_page=true
     4. ?first=2&cursor=2 returns run [1], has_next_page=false, has_previous_page=true

Pagination cursors, total_count, start_index, and has_next/has_previous_page flags all behave correctly.

[rdeepak2002]

Left one last comment, otherwise looks good