Use forked go-workflows migration table option

[rmorlok]

Summary

• Temporarily replace github.com/cschleiden/go-workflows with rmorlok/go-workflows at v0.0.0-20260606194005-c8be9ef9bb4e
• Remove AuthProxy's copied go-workflows SQL migrations and custom golang-migrate runner
• Configure go-workflows sqlite/postgres backends with authproxy_workflows_schema_migrations via WithMigrationsTable
• Add a SQLite regression test proving an existing main schema_migrations table at version 10 no longer collides with workflow migrations

Draft status

This is intentionally draft-only while the go-workflows migration-table option lives in the rmorlok fork. Once the upstream repo has the option, this PR should drop the replace and move back to the upstream module/version.

Refs #539.

Verification

• go test ./internal/workflows ./internal/core ./internal/routes ./internal/tasks ./internal/service/worker ./internal/service/api ./internal/service/public
• go test -tags integration ./oauth2 -run DisconnectRevocation -count=1 (from integration_tests)
• ./scripts/preflight.sh
• go test ./...
• push hook preflight passed

[rmorlok]

Blocked on cschleiden/go-workflows#485 merging.

[github-actions]

Dev environment is ready

Item	Value
URL	https://codex-workflows-fork-migrations.dev.authproxy.net/
Namespace	dev-codex-workflows-fork-migrations
Image tag	pr-543

This comment is updated after each successful deploy.