Reject non-hex characters in EPS uni/u glyph names

Found while testing crates/eps/src/import/text.rs:501-502 (glyph_char)

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

crates/eps/src/import/text.rs

@@ -499,6 +499,7 @@ fn glyph_char(name: &str) -> char {
         return c;
     }
     if let Some(hex) = name.strip_prefix("uni").or_else(|| name.strip_prefix('u'))
+        && hex.chars().all(|c| c.is_ascii_hexdigit())
         && let Some(c) = u32::from_str_radix(hex, 16).ok().and_then(char::from_u32)
     {
         return c;
@@ -508,3 +509,16 @@ fn glyph_char(name: &str) -> char {
         _ => '\u{2022}',
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::glyph_char;
+
+    #[test]
+    fn glyph_char_rejects_plus_in_hex() {
+        assert_eq!(glyph_char("uni20AC"), '€');
+        assert_eq!(glyph_char("u1F600"), '\u{1F600}');
+        assert_eq!(glyph_char("uni+041"), '\u{2022}');
+        assert_eq!(glyph_char("u+41"), '\u{2022}');
+    }
+}