feat: add email_verified_field to identity_providers table in migration

[chenyme]

Summary

Fix identity provider save failures on existing databases by adding an idempotent PostgreSQL baseline migration for the newly added identity_providers.email_verified_field column.

Change type

• Bug fix
• Feature
• Documentation
• Refactor
• Configuration / deployment
• Security hardening
• Other

Affected areas

• Frontend / UI
• Backend / API
• Authentication / authorization
• Conversations / streaming
• Files / RAG / extraction
• Model routing / providers
• MCP / tools
• Billing / payments
• Admin console
• Deployment / Docker / configuration
• Documentation

Verification

• cd backend && go test ./internal/infra/persistence/postgres/...
• cd backend && go test ./internal/application/auth ./internal/transport/http/auth
• git diff --check
• Not run; reason:

Screenshots, API examples, or logs

ERROR: column "email_verified_field" of relation "identity_providers" does not exist (SQLSTATE 42703)

Configuration, migration, and compatibility notes

Adds an idempotent startup migration:

ALTER TABLE "identity_providers"
ADD COLUMN IF NOT EXISTS "email_verified_field" varchar(64) NOT NULL DEFAULT 'email_verified'

Existing deployments will add the missing column on backend restart. No API contract changes. No manual migration is required.

Documentation

• Documentation is not needed for this change.
• Documentation was updated.
• Documentation still needs to be updated.

Security and privacy

• No secrets, tokens, credentials, local config, or personal data are included.
• User data access remains scoped by authenticated user context unless an admin-only path explicitly requires broader access.
• Security-sensitive behavior was reviewed, including authentication, authorization, provider routing, file processing, billing, and admin APIs where relevant.

Checklist

• I searched existing issues and pull requests.
• Changes are focused and do not include unrelated refactors.
• Tests or static verification were run where practical.
• User-facing behavior, deployment steps, API contracts, or configuration changes are documented.
• Generated artifacts are included only when this project explicitly requires them.
• Caches, build output, .pyc files, .env files, and local storage data are not committed.