test: add Bruno API test collections for device authentication

- Device token regeneration tests (success, forbidden, not found, unauthorized)
- OPDS authentication tests (Bearer token, query token)
- Kobo sync tests with token authentication
- Test various authentication methods and error cases

bruno/sync-kobo/get-initialization-url-token.bru

@@ -0,0 +1,40 @@
+meta {
+  name: Kobo Initialization - URL Path Token
+  type: http
+  seq: 4
+}
+
+get {
+  url: {{base_url}}/sync/kobo/{{kobo_device_token}}/v1/initialization
+  body: none
+  auth: none
+}
+
+docs {
+  ## Kobo Initialization - URL Path Token
+
+  Returns initialization data for Kobo device using token in URL path.
+
+  **Method:** GET
+
+  **Endpoint:** /sync/kobo/{kobo_device_token}/v1/initialization
+
+  **Authentication:** URL path parameter (Kobo devices never send Bearer tokens)
+
+  **Path Parameters:**
+  - `kobo_device_token` (string): Device auth token from devices.auth_token
+
+  **Response:** Initialization configuration and settings
+
+  **Status Codes:**
+  - 200: Success (initialization data)
+  - 401: Unauthorized
+  - 403: Device sync disabled
+  - 404: Device not found
+
+  **Important:** Kobo devices use URL path token exclusively, never Bearer header
+
+  **Use Case:** Kobo devices initializing sync connection via stock firmware
+
+  **Note:** This endpoint is called when Kobo first connects to sync server
+}