Confirm subscription endpoint

Cargo.lock

@@ -1217,6 +1217,15 @@ dependencies = [
  "vcpkg",
 ]
 
+[[package]]
+name = "linkify"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f1dfa36d52c581e9ec783a7ce2a5e0143da6237be5811a0b3153fedfdbe9f780"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "litemap"
 version = "0.8.0"
@@ -3373,9 +3382,11 @@ dependencies = [
  "claims",
  "config",
  "fake",
+ "linkify",
  "once_cell",
  "quickcheck",
  "quickcheck_macros",
+ "rand 0.9.2",
  "reqwest",
  "secrecy",
  "serde",