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/devices/regenerate-token-notfound.bru

@@ -0,0 +1,26 @@
+meta {
+  name: Regenerate Device Token - Not Found
+  type: http
+  seq: 4
+}
+
+put {
+  url: {{base_url}}/api/devices/00000000-0000-0000-0000-000000000000/regenerate-token
+  body: none
+  auth: bearer
+}
+
+docs {
+  ## Regenerate Device Token - Not Found
+
+  Tests that token regeneration returns 404 for non-existent devices.
+
+  **Expected Behavior:** Returns 404 Not Found when device UUID doesn't exist
+
+  **Status Codes:**
+  - 404: Device not found
+
+  **Use Case:** Verify proper error handling for invalid device IDs
+
+  **Setup:** Use all-zero UUID (guaranteed to not exist in database)
+}