[ARCHITECTURE][API DRIFT] Consolidate duplicate serverless and Express domain handlers

[BigDella]

Summary

Prompt Hash implements overlapping prompt, version, webhook, and marketplace behavior in both root api/ functions and server/src/ controllers/routes. Security and validation fixes can land in one path while deployments continue serving the other, creating behavior drift.

Repository evidence

• api/prompts/version.ts and server/src/controllers/versioningControllers.ts independently implement prompt-version behavior.
• api/webhooks/* and server/src/routes/webhooks.ts expose parallel webhook stacks.
• Root serverless handlers and the Express application use separate middleware, error mapping, and runtime configuration.

Scope

• Inventory duplicate production entrypoints and select one authoritative domain service per capability.
• Make each deployment adapter call shared validation, authorization, and business logic.
• Add parity tests or remove unsupported duplicate routes with an explicit compatibility plan.

Acceptance criteria

• A security or validation rule has one authoritative implementation regardless of deployment adapter.
• Supported serverless and Express endpoints pass the same contract fixtures.
• Deprecated duplicate routes have documented migration and cannot remain silently deployed.

Tests

• Cross-adapter contract tests for prompt versioning and webhooks, auth/error parity, and a CI check that detects new duplicated domain logic.

Non-goals

• Forcing a hosting-platform migration or rewriting unrelated frontend code.

[Chidi-Dev1]

I’d love the opportunity to resolve this issue. Kindly assign it to me.

[Owolabenjade]

Hello maintainer, I want to work on this issue.

[rupesh-kumar-sah]

Hi everyone,

I am interested in working on this issue.
Plan:

1. Build out the handlers for [ARCHITECTURE][API DRIFT] Consolidate duplicate serverless and Express domain handlers ensuring proper HTTP status codes and error propagation.
2. Add integration test suites for standard invocations and boundary/error conditions.

Ready to deliver a clean, tested PR within 12–24 hours. Please assign!