User Story
As a backend developer, I want to store bundler and paymaster URLs in the networks table so that new networks can be added without code changes and URLs can be updated via the database.

Acceptance Criteria

1. GIVEN the networks table is updated
   WHEN checking its schema
   THEN it should have new columns for bundler_url and paymaster_url

2. GIVEN a new network is added
   WHEN specifying its AA service URLs
   THEN they should be configurable via database entry

3. GIVEN the code changes are deployed
   WHEN getting AA service provider details
   THEN it should be inferred from the supported URL patterns ("api.stackup", "api.biconomy", or "api.pimlico")

Tech Details

• Add new columns to networks table:

  • bundler_url (string, optional)
  • paymaster_url (string, optional)

• Update Network entity (ent/schema/network.go):

  • Add new fields to Network.Fields()
  • Bundle migration with existing networks data

• Update userop.go:

  • Remove URL lookups from Configuration struct
  • Fetch URLs from database in getEndpoints()
  • Add URL pattern check for supported AA services: stackup, pimlico, biconomy
  • Update error messages for clarity

• Generate ent migration file for postgres db (refer https://entgo.io/docs/getting-started#generating-migrations)

Notes/Assumptions

• AA service provider can be detected from URL patterns for Stackup, Biconomy, and Pimlico
• Existing networks will need their AA details migrated
• Not all networks will have AA service enabled
• Maintain backward compatibility during migration

Open Questions

• What happens if a URL doesn't match any of the supported AA service patterns?