[Job Launcher] Job creation to be job type agnostic

[portuu3]

Description
Refactor Job Launcher Server job creation to be job-type agnostic by introducing a new create endpoint that accepts a generic payload instead of job-type-specific inputs. The new request should accept: manifestUrl, manifestHash, fundAmount, fundToken, network (existing enum), and taskSize (int > 0). The server must validate the manifest by fetching it and verifying the provided SHA-1 hash (crypto.createHash('sha1').update(data).digest('hex')).

Motivation
Current job creation is coupled to specific job types, which makes the API harder to extend and increases backend branching/maintenance. A manifest-driven, job-type-agnostic create flow simplifies the API contract, moves job-specific details into the manifest, and makes it easier to support new job types without changing the creation endpoint.

Implementation details

• Add a new job creation endpoint (new route/version) and keep response shape aligned with current behavior where possible.
• Define a new create-job DTO with:
  • manifestUrl: string (URL validation)
  • manifestHash: string (SHA-1 hex format validation)
  • fundAmount: number (in payment token)
  • paymenToken: string ????
  • fundToken: string (use existing token conventions/enums if available)
  • network: ExistingNetworkEnum
  • taskSize: number (integer, > 0)
• Remove jobType from the new endpoint request payload.
• Implement manifest verification in the creation flow:
  • Fetch manifest content from manifestUrl
  • Compute SHA-1 hash using existing utility behavior (crypto.createHash('sha1').update(data).digest('hex'))
  • Reject request if computed hash does not match manifestHash
• Update job creation service flow to avoid job-type-specific branching at request parsing time (manifest becomes the source of type-specific details).
• Update job entity to remove job type.
• Add/update tests.
• Update docs and examples to document the new endpoint and payload.