feat(ats): support workable connection and oauth credentials (#551) - #660

Summary

Adds support for Workable as an ATS integration within Revert APIs, enabling users to establish connection credentials via Workable API Access Tokens (direct connection) and OAuth2 authorization code flows.

Resolves #551

/claim #551

Key Changes

• Prisma Schema (schema.prisma): Added workable to enum TP_ID for database-backed connection modeling.
• Provider Registry (constants/common.ts): Registered workable in ATS_TP_ID, mapIntegrationIdToIntegrationName, and defined DEFAULT_SCOPE[TP_ID.workable].
• Workable Auth Handler (authHandlers/workable.ts): Implemented WorkableAuthHandler with:
  • handleBasicAuth(): Securely persists Workable API access tokens into xprisma.connections and emits sendConnectionAddedEvent.
  • handleOAuth(): Handles standard OAuth2 code token exchange with Workable's token endpoint (https://oauth.workable.com/oauth/token).
• Auth Router (routes/v1/ats/auth.ts): Dispatches TP_ID.workable callbacks to the appropriate handler.
• Metadata Catalog (services/metadata.ts): Exposes Workable integration details in the metadata catalogue.
• Automated Tests (workable.test.ts): Added unit tests verifying provider mappings, default scopes, and handler exports.

Testing & Verification

• Tested unit suite (bun test packages/backend/routes/v1/ats/authHandlers/workable.test.ts): 100% pass (3/3 tests).
• Zero regressions against existing backend test suite.

Bounty Payout Address (USDC on Base):
0xf50Bdf054542974Eef886cBBCDa8c533A65C58F8