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/testdata/segment.yaml

@@ -0,0 +1,116 @@
+---
+# Hand-authored cassette for the Segment Public API (US host; Bearer token
+# stripped by the recorder). GET /users returns members without roles, so each
+# member's roles are fetched via GET /users/{id} (the N+1); GET /invites adds a
+# pending invite as an inactive member. Two synthetic users cover the
+# Workspace Owner (admin) and a resource-scoped read-only role; the envelope
+# (data.users / data.user.permissions / data.invites, data.pagination.next) and
+# the UserV1 / PermissionV1 shapes mirror the live API.
+version: 2
+interactions:
+    - id: 0
+      request:
+        proto: HTTP/1.1
+        proto_major: 1
+        proto_minor: 1
+        content_length: 0
+        host: api.segmentapis.com
+        form:
+            pagination.count:
+                - "200"
+        headers:
+            Accept:
+                - application/json
+        url: https://api.segmentapis.com/users?pagination.count=200
+        method: GET
+      response:
+        proto: HTTP/2.0
+        proto_major: 2
+        proto_minor: 0
+        content_length: -1
+        uncompressed: true
+        body: '{"data":{"users":[{"id":"sgJDWk3K21k6LE3tLU9nRK","name":"","email":"papi@example.com"},{"id":"i2VTJURQprNfqdwjLFPWYx","name":"Sloth","email":"sloth@example.com"}],"pagination":{"current":"MA=="}}}'
+        headers:
+            Content-Type:
+                - application/json
+        status: 200 OK
+        code: 200
+        duration: 100ms
+    - id: 1
+      request:
+        proto: HTTP/1.1
+        proto_major: 1
+        proto_minor: 1
+        content_length: 0
+        host: api.segmentapis.com
+        headers:
+            Accept:
+                - application/json
+        url: https://api.segmentapis.com/users/sgJDWk3K21k6LE3tLU9nRK
+        method: GET
+      response:
+        proto: HTTP/2.0
+        proto_major: 2
+        proto_minor: 0
+        content_length: -1
+        uncompressed: true
+        body: '{"data":{"user":{"id":"sgJDWk3K21k6LE3tLU9nRK","name":"","email":"papi@example.com","permissions":[{"roleId":"1WDUuRLxv84rrfCNUwvkrRtkxnS","roleName":"Workspace Owner","resources":[{"id":"9aQ1Lj62S4bomZKLF4DPqW","type":"WORKSPACE","labels":[]}]}]}}}'
+        headers:
+            Content-Type:
+                - application/json
+        status: 200 OK
+        code: 200
+        duration: 100ms
+    - id: 2
+      request:
+        proto: HTTP/1.1
+        proto_major: 1
+        proto_minor: 1
+        content_length: 0
+        host: api.segmentapis.com
+        headers:
+            Accept:
+                - application/json
+        url: https://api.segmentapis.com/users/i2VTJURQprNfqdwjLFPWYx
+        method: GET
+      response:
+        proto: HTTP/2.0
+        proto_major: 2
+        proto_minor: 0
+        content_length: -1
+        uncompressed: true
+        body: '{"data":{"user":{"id":"i2VTJURQprNfqdwjLFPWYx","name":"Sloth","email":"sloth@example.com","permissions":[{"roleId":"2ABxYz84rrfCNUwvkrRtkxnT","roleName":"Source Read-only","resources":[{"id":"src_1a2b3c","type":"SOURCE","labels":[]}]}]}}}'
+        headers:
+            Content-Type:
+                - application/json
+        status: 200 OK
+        code: 200
+        duration: 100ms
+    - id: 3
+      request:
+        proto: HTTP/1.1
+        proto_major: 1
+        proto_minor: 1
+        content_length: 0
+        host: api.segmentapis.com
+        form:
+            pagination.count:
+                - "200"
+        headers:
+            Accept:
+                - application/json
+        url: https://api.segmentapis.com/invites?pagination.count=200
+        method: GET
+      response:
+        proto: HTTP/2.0
+        proto_major: 2
+        proto_minor: 0
+        content_length: -1
+        uncompressed: true
+        body: '{"data":{"invites":["foo@example.com"],"pagination":{"current":"MA=="}}}'
+        headers:
+            Content-Type:
+                - application/json
+        status: 200 OK
+        code: 200
+        duration: 100ms