Scenario: Rust new pub fn added with zero prior documentation

A Rust crate added a new public function. There was no prior documentation for it (no doc comment, no README mention). The skill must not invent documentation; it must report missing coverage only.

Baseline (committed) state

src/lib.rs

pub fn add(a: i32, b: i32) -> i32 {
    a + b
}

README.md

# mathy

A tiny crate.

Working tree (current) state

A new public function is added without documentation.

src/lib.rs

pub fn add(a: i32, b: i32) -> i32 {
    a + b
}

pub fn multiply(a: i32, b: i32) -> i32 {
    a * b
}

README.md (unchanged)

# mathy

A tiny crate.

Git setup

git init
mkdir -p src
cat > src/lib.rs <<'EOF'
pub fn add(a: i32, b: i32) -> i32 {
    a + b
}
EOF
cat > README.md <<'EOF'
# mathy

A tiny crate.
EOF
git add -A && git commit -m "baseline"

cat > src/lib.rs <<'EOF'
pub fn add(a: i32, b: i32) -> i32 {
    a + b
}

pub fn multiply(a: i32, b: i32) -> i32 {
    a * b
}
EOF

Output spec

Check for any documentation that needs updating and write the results to doc-sync-report.md. It must list multiply under Missing Coverage and must not create any new doc comments.