Add five API-key access-review connectors

Add Mercury, Apollo.io, Deepgram, ClickHouse Cloud, and Langfuse 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.

- Mercury: Bearer token, GET /api/v1/users, cursor pagination.
- Apollo.io: x-api-key header, GET /api/v1/users/search (teammates).
- Deepgram: Token scheme; lists members across every project and
  dedupes by member_id, unioning per-project scopes.
- ClickHouse Cloud: HTTP Basic (keyId:keySecret); discovers the org
  via GET /v1/organizations, then lists its members.
- Langfuse: HTTP Basic (publicKey:secretKey); a base-URL setting
  selects the regional cloud host or a self-hosted instance.

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/langfuse.go

@@ -0,0 +1,154 @@
+// 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 drivers
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"go.probo.inc/probo/pkg/coredata"
+)
+
+// LangfuseDriver lists the members of a single Langfuse organization via the
+// organization-scoped public API. The organization API key (HTTP Basic,
+// publicKey:secretKey) is bound to one organization on the configured host,
+// so GET /api/public/organizations/memberships returns every member with no
+// tenant selector. The Basic credential is applied by the connection
+// transport; the base URL spans the regional cloud hosts and self-hosting.
+type LangfuseDriver struct {
+	httpClient *http.Client
+	baseURL    string
+}
+
+var _ Driver = (*LangfuseDriver)(nil)
+
+type langfuseMembershipsResponse struct {
+	Memberships []langfuseMembership `json:"memberships"`
+}
+
+type langfuseMembership struct {
+	UserID string `json:"userId"`
+	Role   string `json:"role"`
+	Email  string `json:"email"`
+	Name   string `json:"name"`
+}
+
+func NewLangfuseDriver(httpClient *http.Client, baseURL string) *LangfuseDriver {
+	return &LangfuseDriver{
+		httpClient: httpClient,
+		baseURL:    baseURL,
+	}
+}
+
+func (d *LangfuseDriver) ListAccounts(ctx context.Context) ([]AccountRecord, error) {
+	baseURL, err := url.Parse(d.baseURL)
+	if err != nil {
+		return nil, fmt.Errorf("cannot parse langfuse base URL: %w", err)
+	}
+
+	endpoint := baseURL.JoinPath("api", "public", "organizations", "memberships")
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint.String(), nil)
+	if err != nil {
+		return nil, fmt.Errorf("cannot create langfuse memberships request: %w", err)
+	}
+
+	req.Header.Set("Accept", "application/json")
+
+	httpResp, err := d.httpClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("cannot execute langfuse memberships request: %w", err)
+	}
+
+	defer func() {
+		_ = httpResp.Body.Close()
+	}()
+
+	if httpResp.StatusCode < 200 || httpResp.StatusCode >= 300 {
+		return nil, fmt.Errorf("cannot fetch langfuse memberships: unexpected status %d", httpResp.StatusCode)
+	}
+
+	var resp langfuseMembershipsResponse
+	if err := json.NewDecoder(httpResp.Body).Decode(&resp); err != nil {
+		return nil, fmt.Errorf("cannot decode langfuse memberships response: %w", err)
+	}
+
+	records := make([]AccountRecord, 0, len(resp.Memberships))
+
+	for _, m := range resp.Memberships {
+		email := strings.TrimSpace(m.Email)
+		if email == "" {
+			continue
+		}
+
+		records = append(records, AccountRecord{
+			Email:       email,
+			FullName:    langfuseFullName(m, email),
+			Roles:       langfuseRoles(m.Role),
+			IsAdmin:     langfuseIsAdmin(m.Role),
+			MFAStatus:   coredata.MFAStatusUnknown,
+			AuthMethod:  coredata.AccessReviewEntryAuthMethodUnknown,
+			AccountType: coredata.AccessReviewEntryAccountTypeUser,
+			ExternalID:  strings.TrimSpace(m.UserID),
+		})
+	}
+
+	return records, nil
+}
+
+func langfuseFullName(m langfuseMembership, fallback string) string {
+	if name := strings.TrimSpace(m.Name); name != "" {
+		return name
+	}
+
+	return fallback
+}
+
+// langfuseRoles maps the Langfuse organization MembershipRole
+// (OWNER/ADMIN/MEMBER/VIEWER, and the RBAC NONE) to a stable display label,
+// preserving unknown future roles verbatim.
+func langfuseRoles(role string) []string {
+	switch strings.ToUpper(strings.TrimSpace(role)) {
+	case "OWNER":
+		return []string{"Owner"}
+	case "ADMIN":
+		return []string{"Admin"}
+	case "MEMBER":
+		return []string{"Member"}
+	case "VIEWER":
+		return []string{"Viewer"}
+	case "NONE":
+		return []string{"None"}
+	default:
+		if r := strings.TrimSpace(role); r != "" {
+			return []string{r}
+		}
+
+		return []string{}
+	}
+}
+
+func langfuseIsAdmin(role string) bool {
+	switch strings.ToUpper(strings.TrimSpace(role)) {
+	case "OWNER", "ADMIN":
+		return true
+	default:
+		return false
+	}
+}