Move environment abstraction into exec server (#15125)

The idea is that codex-exec exposes an Environment struct with services
on it. Each of those is a trait.

Depending on construction parameters passed to Environment they are
either backed by local or remote server but core doesn't see these
differences.

codex-rs/Cargo.lock

@@ -1427,7 +1427,7 @@ dependencies = [
  "codex-chatgpt",
  "codex-cloud-requirements",
  "codex-core",
- "codex-environment",
+ "codex-exec-server",
  "codex-feedback",
  "codex-file-search",
  "codex-login",
@@ -1843,7 +1843,7 @@ dependencies = [
  "codex-client",
  "codex-config",
  "codex-connectors",
- "codex-environment",
+ "codex-exec-server",
  "codex-execpolicy",
  "codex-file-search",
  "codex-git",
@@ -1947,17 +1947,6 @@ dependencies = [
  "serde_json",
 ]
 
-[[package]]
-name = "codex-environment"
-version = "0.0.0"
-dependencies = [
- "async-trait",
- "codex-utils-absolute-path",
- "pretty_assertions",
- "tempfile",
- "tokio",
-]
-
 [[package]]
 name = "codex-exec"
 version = "0.0.0"
@@ -2008,13 +1997,16 @@ name = "codex-exec-server"
 version = "0.0.0"
 dependencies = [
  "anyhow",
+ "async-trait",
  "clap",
  "codex-app-server-protocol",
+ "codex-utils-absolute-path",
  "codex-utils-cargo-bin",
  "futures",
  "pretty_assertions",
  "serde",
  "serde_json",
+ "tempfile",
  "thiserror 2.0.18",
  "tokio",
  "tokio-tungstenite",