feat: add Workable ATS integration - #663

Resolves #551
Fixes #551

/claim #551

Summary of Changes

This PR implements the full, production-grade Workable ATS integration across Revert backend, Prisma database schema/seed, unified CRM transforms, client UI, and JS SDK.

1. Database & Configuration

• Prisma Schema & Enum: Added workable to TP_ID enum in schema.prisma.
• Database Migration: Added SQL migration 20260907130000_workable_enum/migration.sql with ALTER TYPE "TP_ID" ADD VALUE 'workable';.
• Constants: Registered workable in ATS_TP_ID, DEFAULT_SCOPE, and mapIntegrationIdToIntegrationName.
• Environment & Config: Added WORKABLE_CLIENT_ID, WORKABLE_CLIENT_SECRET, WORKABLE_AUTH_URL, and WORKABLE_TOKEN_URL in config.ts and .env.example.
• Database Seed & Field Mappings: Injected 77 field mappings across Candidate, Job, Offer, and Department in fields.ts and enabled seeding in seed.ts.

2. Dual Authentication & Routing

• WorkableAuthHandler: Implemented dual authentication in routes/v1/ats/authHandlers/workable.ts:
  • Direct API Access Token (Basic Auth): Takes token from Workable Settings > Integrations > Access Token, persists to connection with active status, and emits sendConnectionAddedEvent.
  • OAuth2 Flow: Exchanges code for access token via Workable OAuth token endpoint, fetches account profile, and saves connection.
• OAuth Callback: Wired /oauth-callback in routes/v1/ats/auth.ts to automatically route between OAuth and Direct API Token based on available app credentials.
• Token Refresh & Metadata: Wired automated refresh in services/auth.ts and registered official Workable logo/metadata in services/metadata.ts.

3. Unified ATS Endpoints

• Candidate Service (services/ats/candidate.ts):
  • getCandidate: Fetches /candidates/:id and unifies.
  • getCandidates: Fetches /candidates (or /jobs/:shortcode/candidates) with cursor pagination and unifies.
  • createCandidate: Creates candidate; routes to /jobs/:shortcode/candidates if shortcode or job_id is supplied, else /candidates.
  • updateCandidate: Updates candidate via PATCH /candidates/:id.
  • deleteCandidate: Deletes candidate via DELETE /candidates/:id.
• Job Service (services/ats/job.ts):
  • getJob: Fetches /jobs/:shortcode and unifies.
  • getJobs: Fetches /jobs with cursor pagination and unifies.
  • createJob, updateJob, deleteJob: Standard unsupported responses matching Revert ATS architecture.
• Department Service (services/ats/department.ts):
  • getDepartments: Fetches /departments with cursor pagination and unifies.
  • getDepartment: Resolves specific department from /departments by ID/name.
• Offer Service (services/ats/offer.ts):
  • getOffer: Fetches /offers/:id and unifies.
  • getOffers: Fetches /offers or /candidates/:id/offer and unifies.
• Proxy Service (services/ats/proxy.ts):
  • Passthrough proxy tunneling arbitrary requests to https://{subdomain}.workable.com/spi/v3/{path} with Bearer auth headers.

4. Transforms & Normalizers

• Preprocess Normalizers (helpers/crm/transform/preprocess.ts): Added normalizers for Candidate (names, emails, phones, stages, application shortcodes), Job (shortcode, department, status mapping), Offer (status, candidate/job links), and Department.
• Disunify Payload (helpers/crm/transform/disunify.ts): Added Workable candidate creation payload disunification (candidate: { firstname, lastname, name, email, phone, headline, summary }).

5. Frontend UI & JS SDK

• Edit Credentials (EditCredentials.tsx): Added Subdomain / Organisation URL input and validation check for Workable.
• Client Metadata (enums/metadata.ts): Added Workable app info, description, and logo.
• Client OAuth Callback (oauth/index.tsx): Included workable in ATS /oauth-callback handler.
• JS SDK (packages/js/src/index.ts): Added Workable popup connect flow supporting direct API key modal input or OAuth popup.

Verification & Testing

• 30 Automated Unit Tests (100% PASS):
  ./node_modules/.bin/jest --config=packages/backend/jest.config.json packages/backend/helpers/ats/workable.test.ts --forceExit
  • URL normalization (subdomains, full hosts, https, spi/v3 paths)
  • Bearer auth header generation
  • Collection & resource extraction
  • Cursor pagination parsing (since_id, after_id, cursor, paging.next_id)
  • Authenticated request execution
  • Preprocess normalizers for all 4 ATS entities
  • Candidate creation disunification
  • Basic auth handler execution and webhook emission
• Prettier Code Formatting:
  ./node_modules/.bin/prettier --check <all changed files> -> All matched files use Prettier code style!