fix: validate parse_date calendar dates with chrono

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Cargo.lock

@@ -6228,6 +6228,7 @@ name = "vectorcraft-engine"
 version = "0.20.0"
 dependencies = [
  "cfb",
+ "chrono",
  "craft-docpath",
  "crc32fast",
  "flate2",

crates/engine/Cargo.toml

@@ -38,6 +38,7 @@ vectorcraft-scriptcheck = { workspace = true }
 image = { workspace = true }
 hayro-jpeg2000 = { version = "=0.3.5", default-features = false, features = ["std", "simd"] }
 flate2 = { workspace = true }
+chrono = { workspace = true }
 # The XML parts of Word documents placed as type (place/docx.rs).
 roxmltree = "0.21"
 # The compound file that holds a Word 97-2003 document placed as type (place/doc.rs).

crates/engine/src/cmd/fileio/naming.rs

@@ -111,15 +111,8 @@ pub fn parse_date(s: &str) -> Option<[i64; 6]> {
     }
     let num = |a: usize, b: usize| digits.get(a..b).and_then(|t| t.parse::<i64>().ok());
     let (y, m, d) = (num(0, 4)?, num(4, 6)?, num(6, 8)?);
-    let leap = (y % 4 == 0 && y % 100 != 0) || y % 400 == 0;
-    let days = match m {
-        1 | 3 | 5 | 7 | 8 | 10 | 12 => 31,
-        4 | 6 | 9 | 11 => 30,
-        2 if leap => 29,
-        2 => 28,
-        _ => return None,
-    };
-    (1..=days).contains(&d).then_some([y, m, d, 0, 0, 0])
+    chrono::NaiveDate::from_ymd_opt(i32::try_from(y).ok()?, u32::try_from(m).ok()?, u32::try_from(d).ok()?)?;
+    Some([y, m, d, 0, 0, 0])
 }
 
 #[cfg(test)]