chore: decouple rust SDK into its own Cargo workspace

Stop treating sdk/rust as a member of the dstack core workspace. The
packages only share a protocol with guest-agent and do not need to be
resolved when building guest binaries.

- make sdk/rust a standalone workspace with its own lockfile
- move no_std_check next to the SDK types it validates
- drop sdk/rust rsync from the dstack-guest Yocto recipe
- point SDK CI and crates.io publish at sdk/rust/Cargo.toml

Author: kvinwang

.github/scripts/cargo-publish-idempotent.sh

@@ -11,7 +11,7 @@ set -euo pipefail
 
 crate=${1:?missing crate name}
 
-if output=$(cargo publish --manifest-path dstack/Cargo.toml -p "$crate" 2>&1); then
+if output=$(cargo publish --manifest-path sdk/rust/Cargo.toml -p "$crate" 2>&1); then
     echo "$output"
     exit 0
 fi

.github/workflows/rust-sdk-release.yml

@@ -53,8 +53,8 @@ jobs:
                   pkg_version("sdk/rust/types/Cargo.toml")),
               ("sdk/rust/Cargo.toml [package.version]",
                   pkg_version("sdk/rust/Cargo.toml")),
-              ("dstack/Cargo.toml [workspace.dependencies.dstack-sdk-types.version]",
-                  ws_dep_version("dstack/Cargo.toml", "dstack-sdk-types")),
+              ("sdk/rust/Cargo.toml [workspace.dependencies.dstack-sdk-types.version]",
+                  ws_dep_version("sdk/rust/Cargo.toml", "dstack-sdk-types")),
           ]
 
           fail = False
@@ -64,7 +64,7 @@ jobs:
               print(f"  {'OK ' if ok else 'BAD'}  {label}: {got}")
 
           if fail:
-              print(f"\ntag is dstack-sdk-v{want}; bump all three to {want} before tagging.",
+              print(f"\ntag is dstack-sdk-v{want}; bump SDK package versions to {want} before tagging.",
                     file=sys.stderr)
               sys.exit(1)
           PY

.github/workflows/sdk.yaml

@@ -34,9 +34,9 @@ jobs:
 
       - name: Verify WASM compilation
         # Ensures SDK types can be used in smart contracts
-        run: cargo check --manifest-path dstack/Cargo.toml --target=wasm32-unknown-unknown -p dstack-sdk-types
+        run: cargo check --manifest-path sdk/rust/Cargo.toml --target=wasm32-unknown-unknown -p dstack-sdk-types
 
       - name: Verify no_std compatibility
         run: |
-          cargo test --manifest-path dstack/Cargo.toml -p dstack-sdk-types --test no_std_test --no-default-features
-          cargo check --manifest-path dstack/Cargo.toml -p no_std_check --target thumbv6m-none-eabi
+          cargo test --manifest-path sdk/rust/Cargo.toml -p dstack-sdk-types --test no_std_test --no-default-features
+          cargo check --manifest-path sdk/rust/Cargo.toml -p no_std_check --target thumbv6m-none-eabi