Add four API-key access-review connectors

Add Pylon, OpenRouter, incident.io and Brevo as access-review connectors.
All are API-key, single-tenant providers (Pattern 3): the key identifies
one tenant, so there is no OAuth flow, picker UI, or bootstrap/helm
configuration.

- Pylon: Bearer token, GET /users; resolves each user's opaque role_id to
  a role name via GET /user-roles, with cursor pagination.
- OpenRouter: Bearer management key, GET /api/v1/organization/members. The
  endpoint requires an organization account -- a personal key authenticates
  but returns 404 -- so the connection probe rejects 404 on top of 401/403
  (doProbeRequest gained an opt-in extra-reject set) to surface a non-org
  key at connect time instead of mid-campaign.
- incident.io: Bearer token, GET /v2/users. Its OAuth is outbound-only, so
  the API key is the inbound path; live base_role/custom_roles take
  precedence over the deprecated role enum.
- Brevo: API key in the api-key header (Registration.APIKeyHeader), GET
  /v3/organization/invited/users. A live recording corrected the documented
  schema: is_owner is a JSON boolean (not a string) and an id field is
  present, so it is used as the stable ExternalID.

The OpenRouter and Brevo cassettes are anonymized live recordings; Pylon
and incident.io use hand-authored fixtures (no self-serve test tenant). The
shared three-valued active-status mapping is consolidated into
activeFromStatus in driver.go.

Each adds the enum value, migration, GraphQL binding, provider
Registration, a driver with a cassette-driven test, and a brand logo.

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

pkg/accessreview/drivers/driver.go

@@ -17,6 +17,7 @@ package drivers
 import (
 	"context"
 	"fmt"
+	"strings"
 	"time"
 
 	"go.probo.inc/probo/pkg/coredata"
@@ -83,3 +84,25 @@ func parseRFC3339Ptr(s string) *time.Time {
 
 	return &t
 }
+
+// activeFromStatus maps a provider status string to the three-valued Active
+// signal for providers whose only "live" state is the literal "active" and
+// whose remaining status enum is not otherwise enumerated: "active" → active,
+// an empty status → nil (no signal), and any other non-empty status →
+// inactive. Used by drivers like Pylon and Brevo; a provider with a fully
+// known status enum (e.g. Render's active/inactive) maps its own values
+// explicitly instead, so an unrecognised value stays nil rather than false.
+func activeFromStatus(status string) *bool {
+	switch strings.ToLower(strings.TrimSpace(status)) {
+	case "active":
+		active := true
+
+		return &active
+	case "":
+		return nil
+	default:
+		inactive := false
+
+		return &inactive
+	}
+}