Add Google Analytics, Dotfile, Segment and Square access-review connectors

Two OAuth2 and two API-key connectors:

- Google Analytics (GA4): OAuth2 with both analytics.readonly and
  analytics.manage.users.readonly (readonly alone 403s on the accounts
  list); v1alpha accessBindings enumerated at account and property level
  and merged by email; manual account picker (Pattern 1) with a
  per-connection probe and name resolver; distinct from Google Workspace.
- Dotfile: API key in the X-DOTFILE-API-KEY header (Pattern 3); GET
  /v1/users (owner/admin, suspended_at) with a static probe.
- Segment (Twilio): Public API token as Bearer with a required Region
  setting (US or EU) mapped to the regional host; GET /users plus per-user
  GET /users/{id} for roles and /invites for pending members; per-connection
  BuildProbeURL.
- Square: OAuth2 (EMPLOYEES_READ) or a personal access token (Pattern 3);
  POST /v2/team-members/search returns email/status/is_owner directly, so no
  role resolution; custom probe and name resolver.

Google Analytics and Square are confidential OAuth clients, wired into the
bootstrap OAuth provider list and .env.example. Segment carries a required
extra setting, so the console add-source dialog maps region onto its
segmentRegion API-key input; without that mapping the value is silently
dropped and the create is rejected.

Cassette-backed driver tests plus unit tests for the Segment probe URL and
the bootstrap OAuth provider list.

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

pkg/accessreview/drivers/square.go

@@ -0,0 +1,174 @@
+// 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 (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strings"
+
+	"go.probo.inc/probo/pkg/coredata"
+)
+
+const (
+	squareTeamMembersSearchURL = "https://connect.squareup.com/v2/team-members/search"
+	// squareAPIVersion pins the request version so behavior is deterministic
+	// rather than following the application's console default.
+	squareAPIVersion  = "2026-05-20"
+	squareSearchLimit = 200
+)
+
+// SquareDriver lists the team members of a single Square merchant. A Square
+// token — OAuth Bearer or Personal Access Token — is always scoped to one
+// merchant, so POST /v2/team-members/search returns every team member of that
+// merchant with no tenant selector. The search returns is_owner directly, so
+// there is no role resolution.
+type SquareDriver struct {
+	httpClient *http.Client
+}
+
+var _ Driver = (*SquareDriver)(nil)
+
+type squareTeamMember struct {
+	ID           string `json:"id"`
+	IsOwner      bool   `json:"is_owner"`
+	Status       string `json:"status"`
+	GivenName    string `json:"given_name"`
+	FamilyName   string `json:"family_name"`
+	EmailAddress string `json:"email_address"`
+	CreatedAt    string `json:"created_at"`
+}
+
+type squareSearchResponse struct {
+	TeamMembers []squareTeamMember `json:"team_members"`
+	Cursor      string             `json:"cursor"`
+}
+
+func NewSquareDriver(httpClient *http.Client) *SquareDriver {
+	return &SquareDriver{
+		httpClient: &http.Client{
+			Transport: &retryRoundTripper{
+				next:       httpClient.Transport,
+				maxRetries: 3,
+			},
+		},
+	}
+}
+
+func (d *SquareDriver) ListAccounts(ctx context.Context) ([]AccountRecord, error) {
+	var records []AccountRecord
+
+	cursor := ""
+
+	for range maxPaginationPages {
+		page, err := d.searchTeamMembers(ctx, cursor)
+		if err != nil {
+			return nil, err
+		}
+
+		for _, m := range page.TeamMembers {
+			email := strings.TrimSpace(m.EmailAddress)
+			if email == "" {
+				continue
+			}
+
+			role := "member"
+			if m.IsOwner {
+				role = "owner"
+			}
+
+			records = append(records, AccountRecord{
+				Email:       email,
+				FullName:    squareFullName(m, email),
+				Roles:       ownerMemberRoles(role),
+				Active:      activeFromStatus(m.Status),
+				IsAdmin:     m.IsOwner,
+				MFAStatus:   coredata.MFAStatusUnknown,
+				AuthMethod:  coredata.AccessReviewEntryAuthMethodUnknown,
+				AccountType: coredata.AccessReviewEntryAccountTypeUser,
+				CreatedAt:   parseRFC3339Ptr(m.CreatedAt),
+				ExternalID:  m.ID,
+			})
+		}
+
+		if page.Cursor == "" {
+			return records, nil
+		}
+
+		cursor = page.Cursor
+	}
+
+	return nil, fmt.Errorf("cannot list all square accounts: %w", ErrPaginationLimitReached)
+}
+
+func (d *SquareDriver) searchTeamMembers(ctx context.Context, cursor string) (*squareSearchResponse, error) {
+	// No query filter: return team members of every status (ACTIVE and
+	// INACTIVE) so deactivated members are reviewed too.
+	reqBody := struct {
+		Limit  int    `json:"limit"`
+		Cursor string `json:"cursor,omitempty"`
+	}{
+		Limit:  squareSearchLimit,
+		Cursor: cursor,
+	}
+
+	body, err := json.Marshal(reqBody)
+	if err != nil {
+		return nil, fmt.Errorf("cannot marshal square search request: %w", err)
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, squareTeamMembersSearchURL, bytes.NewReader(body))
+	if err != nil {
+		return nil, fmt.Errorf("cannot create square team members request: %w", err)
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Accept", "application/json")
+	req.Header.Set("Square-Version", squareAPIVersion)
+
+	httpResp, err := d.httpClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("cannot execute square team members request: %w", err)
+	}
+
+	defer func() {
+		_ = httpResp.Body.Close()
+	}()
+
+	if httpResp.StatusCode < 200 || httpResp.StatusCode >= 300 {
+		return nil, fmt.Errorf("cannot fetch square team members: unexpected status %d", httpResp.StatusCode)
+	}
+
+	var resp squareSearchResponse
+	if err := json.NewDecoder(httpResp.Body).Decode(&resp); err != nil {
+		return nil, fmt.Errorf("cannot decode square team members response: %w", err)
+	}
+
+	return &resp, nil
+}
+
+// squareFullName joins the team member's given and family names, falling back
+// to the email when Square exposes neither.
+func squareFullName(m squareTeamMember, email string) string {
+	name := strings.TrimSpace(strings.TrimSpace(m.GivenName) + " " + strings.TrimSpace(m.FamilyName))
+	if name == "" {
+		return email
+	}
+
+	return name
+}