fix(dashboard): add merged stage to maintainer pipeline board (#88)

[ghzhost]

Summary

Closes #88

Adds the missing merged stage to pipelineStages in MaintainerDashboardPage so that bounties whose pull requests have been merged (awaiting automatic escrow payout release) are properly rendered on the maintainer Kanban pipeline board.

Changes Made

1. Pipeline stages update (src/app/dashboard/maintainer/page.tsx):
   • Added { status: "merged", label: "Merged" } to pipelineStages.
   • Exported pipelineStages and PipelineColumn for testing and maintainability.
2. Escrow and Stage Alignment:
   • Re-aligned the pipeline board stages with the totalEscrow stat card calculation (which retains "merged" bounties with locked escrow).
   • Terminal/completed statuses (paid, refunded, expired) remain intentionally omitted from the active in-flight pipeline board.
3. Tests Added (src/app/dashboard/maintainer/MaintainerDashboard.test.ts):
   • Verified presence and label of merged status in pipelineStages.
   • Verified consistency between active pipeline statuses and non-excluded escrow statuses.
   • Tested that a bounty with status: "merged" is properly captured and rendered under the merged column.
4. Test Environment (jest.setup.ts):
   • Set fallback NEXT_PUBLIC_STELLAR_NETWORK="TESTNET" in Jest setup to satisfy environment validation during test suite execution.

Verification

• Ran Jest unit test suite: all test cases in MaintainerDashboard.test.ts passed cleanly.

[vercel]

Someone is attempting to deploy a commit to the chonilius' projects Team on Vercel.

A member of the Team first needs to authorize it.