chore: remove cli, stale docs, and release notes

CLI was removed in a previous commit but workspace Cargo.toml and source
files were not cleaned up. Remove cli from workspace members to prevent
CI format/clippy from trying to compile a removed package.

Author: RoyLin

Cargo.toml

@@ -1,8 +1,7 @@
 [workspace]
 resolver = "2"
 members = [
-    "core",
-    "cli",
+    "core"
 ]
 # Native SDK crates require special toolchains (Python/Node.js)
 # Build them individually: cargo build -p a3s-code-node / a3s-code-py