fix(ci): use full path to bats for kcov coverage

kcov spawns a subprocess that doesn't inherit the npm PATH, so
the 'bats' command wasn't found. Use the full path to the bats
binary in node_modules/.bin/ to fix coverage measurement.

.github/workflows/test.yml

@@ -95,17 +95,20 @@ jobs:
       run: |
         mkdir -p coverage
 
+        # Use full path to bats since kcov subprocess doesn't inherit npm PATH
+        BATS_CMD="$(pwd)/node_modules/.bin/bats"
+
         # Run CLI parsing tests under kcov
         kcov --include-path="$(pwd)/ralph_loop.sh,$(pwd)/lib" \
              --exclude-pattern=tests/,node_modules/ \
              coverage/cli-parsing \
-             bash -c "bats tests/unit/test_cli_parsing.bats" || true
+             bash -c "$BATS_CMD tests/unit/test_cli_parsing.bats" || true
 
         # Run all unit tests under kcov for comprehensive coverage
         kcov --include-path="$(pwd)/ralph_loop.sh,$(pwd)/lib" \
              --exclude-pattern=tests/,node_modules/ \
              coverage/all-unit \
-             bash -c "bats tests/unit/" || true
+             bash -c "$BATS_CMD tests/unit/" || true
 
     - name: Parse coverage results
       id: coverage