move subzero_core to proxy libs (#12742)

We have a dedicated libs folder for proxy related libraries. Let's move
the subzero_core stub there.

proxy/Cargo.toml

@@ -110,7 +110,7 @@ zerocopy.workspace = true
 # uncomment this to use the real subzero-core crate
 # subzero-core = { git = "https://github.com/neondatabase/subzero", rev = "396264617e78e8be428682f87469bb25429af88a", features = ["postgresql"], optional = true }
 # this is a stub for the subzero-core crate
-subzero-core = { path = "./subzero_core", features = ["postgresql"], optional = true}
+subzero-core = { path = "../libs/proxy/subzero_core", features = ["postgresql"], optional = true}
 ouroboros = { version = "0.18", optional = true }
 
 # jwt stuff

proxy/subzero_core/.gitignore

@@ -1,2 +0,0 @@
-target
-Cargo.lock

proxy/subzero_core/Cargo.toml

@@ -1,12 +0,0 @@
-# This is a stub for the subzero-core crate.
-[package]
-name = "subzero-core"
-version = "3.0.1"
-edition = "2024"
-publish = false # "private"!
-
-[features]
-default = []
-postgresql = []
-
-[dependencies]

proxy/subzero_core/src/lib.rs

@@ -1 +0,0 @@
-// This is a stub for the subzero-core crate.