ACP champagne (#35609)

cherry pick changes from #35510 onto latest main

Release Notes:

- N/A

---------

Co-authored-by: Nathan Sobo <nathan@zed.dev>
Co-authored-by: Antonio Scandurra <me@as-cii.com>
Co-authored-by: Lukas Wirth <lukas@zed.dev>

crates/agent2/Cargo.toml

@@ -0,0 +1,53 @@
+[package]
+name = "agent2"
+version = "0.1.0"
+edition = "2021"
+license = "GPL-3.0-or-later"
+publish = false
+
+[lib]
+path = "src/agent2.rs"
+
+[lints]
+workspace = true
+
+[dependencies]
+acp_thread.workspace = true
+agent-client-protocol.workspace = true
+agent_servers.workspace = true
+anyhow.workspace = true
+cloud_llm_client.workspace = true
+collections.workspace = true
+fs.workspace = true
+futures.workspace = true
+gpui.workspace = true
+handlebars = { workspace = true, features = ["rust-embed"] }
+indoc.workspace = true
+language_model.workspace = true
+language_models.workspace = true
+log.workspace = true
+project.workspace = true
+rust-embed.workspace = true
+schemars.workspace = true
+serde.workspace = true
+serde_json.workspace = true
+settings.workspace = true
+smol.workspace = true
+ui.workspace = true
+util.workspace = true
+uuid.workspace = true
+worktree.workspace = true
+workspace-hack.workspace = true
+
+[dev-dependencies]
+ctor.workspace = true
+client = { workspace = true, "features" = ["test-support"] }
+env_logger.workspace = true
+fs = { workspace = true, "features" = ["test-support"] }
+gpui = { workspace = true, "features" = ["test-support"] }
+gpui_tokio.workspace = true
+language_model = { workspace = true, "features" = ["test-support"] }
+project = { workspace = true, "features" = ["test-support"] }
+reqwest_client.workspace = true
+settings = { workspace = true, "features" = ["test-support"] }
+worktree = { workspace = true, "features" = ["test-support"] }