API Endpoint Verification & Schema Capture

[matKlju]

AS A Service-Module developer
I WANT a backend-run Test URL that verifies API endpoints and stores verification results + response schema
SO THAT verified APIs and schemas are shared globally without blocking service creation (#871)

Description

Implement one shared backend Test URL operation used by:

• Global API create/edit modal
• Canvas-level API node edit modal
• API varamu page (Teenused → API-d)

Acceptance Criteria

Execution

• Single backend verification logic used by all UIs
• Request built from:
  • Stored endpoint definition (method, path/url/openApiUrl)
  • User-provided test values (params, headers, body)
• Supported methods: GET, POST
• Explicit safety bounds: timeoutMs, maxResponseBytes
• JSON object-root and array-root responses supported

Persistence

• Test inputs are not persisted
• Persisted fields:
  • verificationStatus ∈ { unverified, verified, failed }
  • lastTestAt
  • lastStatusCode
  • schemaCaptured
  • schemaStored (normalized, stable schema)

Schema overwrite rule

• On successful test (2xx):
  • schemaStored is overwritten with the newly captured schema
  • schemaCaptured = true
  • verificationStatus = verified
• On failed test (non-2xx, timeout, network error):
  • verificationStatus = failed
  • schemaCaptured = false
  • schemaStored is NOT overwritten (last known good schema is preserved)
• Empty body (204 / {}) → treated as successful test with empty schema

UI Contract

• Verification state shown consistently in all UIs
• Verified + schemaCaptured → response fields available in Assign
• Unverified/failed → explicit warning
• Save/create is never blocked by verification state

Concurrency & Errors

• Concurrent runs → last write wins
• Optional UI-safe error category persisted
  (validation | network | timeout | http | non_json | unknown)