Add Better Stack access review connector

Better Stack exposes team members and pending invitations through its
Uptime API. Wire it as an access-review connector so a Better Stack
team can be reviewed in access-review campaigns.

Better Stack has no third-party OAuth app for listing members (its
OAuth is an end-user MCP sign-in), so the connector authenticates with
a Bearer API token plus the team name that scopes the team-members
listing. The driver paginates /api/v2/team-members, maps roles and
invitation records into account records, and the source name is
resolved from the configured team.

This wires the full surface: the provider enum and migration, the
connector settings, the registry registration with the team-name extra
setting, the GraphQL input and resolver marshaling, the frontend field
mapping and connector logo, and cassette-backed driver tests.

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

pkg/connector/provider/better_stack.go

@@ -0,0 +1,65 @@
+// Copyright (c) 2026 Probo Inc <hello@getprobo.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"
+	"fmt"
+	"net/http"
+	"strings"
+
+	"go.gearno.de/kit/log"
+	"go.probo.inc/probo/pkg/accessreview/drivers"
+	"go.probo.inc/probo/pkg/coredata"
+)
+
+// betterStackRegistration wires the Better Stack Uptime access-review
+// connector. Better Stack has no third-party OAuth app for listing team
+// members (its OAuth is an end-user MCP sign-in), so the connector is
+// API-key only: the operator supplies a Bearer API token plus the team
+// name that scopes the team-members listing.
+func betterStackRegistration() *Registration {
+	return &Registration{
+		Provider:       coredata.ConnectorProviderBetterStack,
+		DisplayName:    "Better Stack",
+		SupportsAPIKey: true,
+		ProbeURL:       "https://betterstack.com/api/v2/team-members",
+		ExtraSettings: []ExtraSetting{
+			{Key: "teamName", Label: "Team Name", Required: true},
+		},
+		NewDriver: func(_ context.Context, c *http.Client, conn *coredata.Connector, _ *log.Logger) (drivers.Driver, error) {
+			s, err := coredata.ConnectorSettings[coredata.BetterStackConnectorSettings](conn)
+			if err != nil {
+				return nil, fmt.Errorf("cannot read better stack connector settings: %w", err)
+			}
+
+			teamName := strings.TrimSpace(s.TeamName)
+			if teamName == "" {
+				return nil, fmt.Errorf("cannot create better stack driver: team_name is required")
+			}
+
+			return drivers.NewBetterStackDriver(c, teamName), nil
+		},
+		NewNameResolver: func(ctx context.Context, _ *http.Client, conn *coredata.Connector, logger *log.Logger) drivers.NameResolver {
+			s, err := coredata.ConnectorSettings[coredata.BetterStackConnectorSettings](conn)
+			if err != nil {
+				logger.ErrorCtx(ctx, "cannot read better stack connector settings", log.Error(err))
+				return nil
+			}
+
+			return drivers.NewBetterStackNameResolver(strings.TrimSpace(s.TeamName))
+		},
+	}
+}