create super strict rust config

crates/the-app/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "the-app"
+version = "0.1.0"
+edition = "2024"
+license = "EUPL-1.2"
+
+[dependencies]
+the-lib.workspace = true
+regex = "*"
+
+[lints]
+workspace = true

crates/the-app/src/main.rs

@@ -0,0 +1,19 @@
+#[must_use]
+pub fn as_u64(number: u8) -> u64 {
+    u64::from(number)
+}
+
+fn main() {
+    let mut nums = vec![1, 2, 3];
+    nums.clear();
+
+    println!("Hello, world! {nums:?}");
+}
+
+#[cfg(test)]
+mod test {
+    #[test]
+    fn trivial() {
+        assert_eq!(1, 1);
+    }
+}

crates/the-lib/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "the-lib"
+version = "0.0.0"
+edition = "2024"
+license = "EUPL-1.2"
+
+[dependencies]
+
+[lints]
+workspace = true

crates/the-lib/src/lib.rs

@@ -0,0 +1,18 @@
+#[must_use]
+pub const fn add(
+    left: u64,
+    right: u64,
+) -> u64 {
+    left + right
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn it_works() {
+        let result = add(2, 2);
+        assert_eq!(result, 4);
+    }
+}