chore: enable clippy check for all workspace members

This also remove `RUSTFLAGS: -D warnings` for test,
as it seems to be redundant and clippy covers everythings

.github/workflows/main.yml

@@ -66,9 +66,7 @@ jobs:
       - uses: actions/checkout@v4
       - run: rustup update stable && rustup default stable
       - run: rustup component add clippy
-      # Only check cargo lib for now
-      # TODO: check every members
-      - run: cargo clippy -p cargo --lib --no-deps -- -D warnings
+      - run: cargo clippy --workspace --all-targets --no-deps -- -D warnings
 
   stale-label:
     runs-on: ubuntu-latest
@@ -110,8 +108,6 @@ jobs:
       CARGO_PROFILE_TEST_DEBUG: 1
       CARGO_INCREMENTAL: 0
       CARGO_PUBLIC_NETWORK_TESTS: 1
-      # Deny warnings on CI to avoid warnings getting into the codebase.
-      RUSTFLAGS: -D warnings
     strategy:
       matrix:
         include: