ci: Use Justfile as single source of truth for CI commands

Replace inline cargo commands in GHA workflows with `just ci`,
`just fuzz-all`, and `just generate-corpus`. This eliminates
duplication between the Justfile and the workflow definitions.

Also add `cargo test --no-default-features` to the `unit` target
and remove `fuzz-all` from the `ci` target (fuzzing runs as a
separate GHA job since it requires a nightly toolchain).

Assisted-by: OpenCode (Claude Opus)

Author: cgwalters

.github/workflows/ci.yaml

@@ -42,16 +42,12 @@ jobs:
         uses: dtolnay/rust-toolchain@stable
         with:
           components: rustfmt, clippy
+      - name: Install just
+        uses: extractions/setup-just@v3
       - name: Cache Dependencies
         uses: Swatinem/rust-cache@v2
-      - name: cargo fmt (check)
-        run: cargo fmt -- --check -l
-      - name: Build
-        run: cargo build
-      - name: Test
-        run: cargo test -- --nocapture --quiet
-      - name: cargo clippy
-        run: cargo clippy -- -D warnings
+      - name: CI (check + test)
+        run: just ci
 
   msrv:
     name: MSRV
@@ -92,22 +88,13 @@ jobs:
         uses: dtolnay/rust-toolchain@nightly
       - name: Install cargo-fuzz
         run: cargo install cargo-fuzz --locked
+      - name: Install just
+        uses: extractions/setup-just@v3
       - name: Cache Dependencies
         uses: Swatinem/rust-cache@v2
         with:
           workspaces: fuzz
       - name: Generate seed corpus
-        run: cargo run --manifest-path fuzz/Cargo.toml --bin generate-corpus
+        run: just generate-corpus
       - name: Fuzz all targets (2 minutes each)
-        run: |
-          mkdir -p fuzz-logs
-          for target in $(cargo +nightly fuzz list); do
-            echo "--- Fuzzing $target (2 min) ---"
-            cargo +nightly fuzz run "$target" -- -max_total_time=120 \
-              > "fuzz-logs/$target.log" 2>&1 \
-              && echo "  $target: OK" \
-              || { echo "::error::Fuzzer $target failed"; cat "fuzz-logs/$target.log"; exit 1; }
-            # Print final stats line
-            tail -1 "fuzz-logs/$target.log"
-          done
-        working-directory: fuzz
+        run: just fuzz-all

.github/workflows/fuzz-extended.yaml

@@ -24,21 +24,13 @@ jobs:
         uses: dtolnay/rust-toolchain@nightly
       - name: Install cargo-fuzz
         run: cargo install cargo-fuzz --locked
+      - name: Install just
+        uses: extractions/setup-just@v3
       - name: Cache Dependencies
         uses: Swatinem/rust-cache@v2
         with:
           workspaces: fuzz
       - name: Generate seed corpus
-        run: cargo run --manifest-path fuzz/Cargo.toml --bin generate-corpus
+        run: just generate-corpus
       - name: Fuzz all targets (15 minutes each)
-        run: |
-          mkdir -p fuzz-logs
-          for target in $(cargo +nightly fuzz list); do
-            echo "--- Fuzzing $target (15 min) ---"
-            cargo +nightly fuzz run "$target" -- -max_total_time=900 \
-              > "fuzz-logs/$target.log" 2>&1 \
-              && echo "  $target: OK" \
-              || { echo "::error::Fuzzer $target failed"; cat "fuzz-logs/$target.log"; exit 1; }
-            tail -1 "fuzz-logs/$target.log"
-          done
-        working-directory: fuzz
+        run: just fuzz-all 900

Justfile

@@ -17,6 +17,7 @@ unit:
     else \
         cargo test; \
     fi
+    cargo test --no-default-features
 
 # Run cross-language interop tests (requires python3, go)
 interop:
@@ -27,8 +28,8 @@ interop:
 # Run all tests
 test-all: unit interop
 
-# Full CI check (format, lint, test, fuzz)
-ci: check unit fuzz-all
+# CI check (format, lint, test); see also fuzz-all
+ci: check unit
 
 # Run Kani formal verification proofs (install: cargo install --locked kani-verifier && cargo kani setup)
 kani: