Add Scaleway, Yousign, Railway and Crisp access-review connectors

Four API-key, single-tenant (Pattern 3) connectors:

- Scaleway: secret key in the X-Auth-Token header plus an Organization ID
  setting; GET /iam/v1alpha1/users (owner/member, status, two-factor),
  per-connection BuildProbeURL.
- Yousign: Bearer API key; GET /v3/users (admin/owner/member, is_active);
  production host with a static probe.
- Railway: Bearer account token; GraphQL me{workspaces{members}} aggregated
  and deduplicated across workspaces; custom probe, since Railway returns
  HTTP 200 with an errors body on a rejected token.
- Crisp: plugin token as HTTP Basic (identifier:key) plus a Website ID
  setting and the X-Crisp-Tier header; GET /v1/website/{id}/operators/list,
  custom probe and name resolver.

Scaleway and Crisp carry a required extra setting, so the console add-source
dialog maps organizationId/websiteId onto their scalewayOrganizationId and
crispWebsiteId API-key inputs; without that mapping the value is silently
dropped and the create is rejected.

Cassette-backed driver tests plus unit tests for the cross-workspace
deduplication, the probe contracts and the role/MFA helpers.

Signed-off-by: Aurélien Sibiril <81782+aureliensibiril@users.noreply.github.com>

pkg/connector/provider/railway.go

@@ -0,0 +1,44 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+package provider
+
+import (
+	"context"
+	"net/http"
+
+	"go.gearno.de/kit/log"
+	"go.probo.inc/probo/pkg/accessreview/drivers"
+	"go.probo.inc/probo/pkg/coredata"
+)
+
+func railwayRegistration() *Registration {
+	return &Registration{
+		Provider:       coredata.ConnectorProviderRailway,
+		DisplayName:    "Railway",
+		SupportsAPIKey: true,
+		// Railway authenticates with an account API token as Authorization:
+		// Bearer. A single GraphQL call resolves the account's workspaces and
+		// their members, so there is nothing to pick (Pattern 3). Railway
+		// returns HTTP 200 with an errors body for a rejected token, so the
+		// probe must inspect the body — hence a custom Probe.
+		Probe: probeRailway,
+		NewDriver: func(_ context.Context, c *http.Client, _ *coredata.Connector, _ *log.Logger) (drivers.Driver, error) {
+			return drivers.NewRailwayDriver(c), nil
+		},
+		NewNameResolver: func(_ context.Context, c *http.Client, _ *coredata.Connector, _ *log.Logger) drivers.NameResolver {
+			return drivers.NewRailwayNameResolver(c)
+		},
+	}
+}