Add Anthropic access-review driver and resolver

The driver lists organization members through the Anthropic Admin API
(GET /v1/organizations/users) with cursor pagination, mapping the role
and the RFC 3339 added_at timestamp. The name resolver reads the
organization name from /v1/organizations/me; a non-2xx response (for
example a revoked key) yields no name rather than making the
source-name worker retry forever. Both send the required
anthropic-version header.

Add a VCR test helper that injects the key via x-api-key so the
cassette stays recordable, and strip x-api-key on save. The cassette
holds synthetic members covering the user, developer, and admin roles.

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

pkg/accessreview/drivers/testdata/anthropic.yaml

@@ -0,0 +1,39 @@
+---
+version: 2
+interactions:
+    - id: 0
+      request:
+        proto: HTTP/1.1
+        proto_major: 1
+        proto_minor: 1
+        content_length: 0
+        host: api.anthropic.com
+        form:
+            limit:
+                - "100"
+        headers:
+            Accept:
+                - application/json
+            Anthropic-Version:
+                - "2023-06-01"
+        url: https://api.anthropic.com/v1/organizations/users?limit=100
+        method: GET
+      response:
+        proto: HTTP/2.0
+        proto_major: 2
+        proto_minor: 0
+        content_length: -1
+        uncompressed: true
+        body: '{"data":[{"id":"user_01WCz1FkmYMm4gnmykNKUu3Q","type":"user","email":"jane@example.com","name":"Jane Doe","role":"user","added_at":"2024-10-30T23:58:27.427722Z"},{"id":"user_01AbCdEfGhIjKlMnOpQrStUv","type":"user","email":"alex@example.com","name":"Alex Martin","role":"developer","added_at":"2025-02-14T09:12:03.001000Z"},{"id":"user_01ZyXwVuTsRqPoNmLkJiHgFe","type":"user","email":"john@example.com","name":"John Smith","role":"admin","added_at":"2026-01-05T16:40:51.500000Z"}],"has_more":false,"first_id":"user_01WCz1FkmYMm4gnmykNKUu3Q","last_id":"user_01ZyXwVuTsRqPoNmLkJiHgFe"}'
+        headers:
+            Content-Type:
+                - application/json
+            Date:
+                - Thu, 28 May 2026 12:55:02 GMT
+            Request-Id:
+                - req_011CRgSyntheticExampleId01
+            Server:
+                - cloudflare
+        status: 200 OK
+        code: 200
+        duration: 199.11175ms