refactor(symfony-string): extract symfony/string into the shirabe-symfony-string crate

Move `Symfony\Component\String` out of shirabe-external-packages and into
its own crate, so the path is `shirabe_symfony_string::ByteString`
instead of `shirabe_external_packages::symfony::string::ByteString`.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

1 files changed, 0 insertions, 45 deletions

diff --git a/crates/shirabe-external-packages/src/symfony/string/byte_string.rs b/crates/shirabe-external-packages/src/symfony/string/byte_string.rs
deleted file mode 100644
index 8ad183e3..00000000
--- a/crates/shirabe-external-packages/src/symfony/string/byte_string.rs
+++ /dev/null
@@ -1,45 +0,0 @@
-//! ref: composer/vendor/symfony/string/ByteString.php
-
-use crate::symfony::string::code_point_string::CodePointString;
-
-#[derive(Debug, Clone)]
-pub struct ByteString {
-    pub(crate) string: String,
-}
-
-impl ByteString {
-    pub fn new(string: &str) -> Self {
-        Self {
-            string: string.to_string(),
-        }
-    }
-
-    /// `from_encoding` is `""` for PHP's `null`.
-    pub fn to_code_point_string(&self, from_encoding: &str) -> CodePointString {
-        // The source `string` is always valid UTF-8 (Rust `String`/`&str` guarantee), so
-        // `preg_match('//u', ...)` always holds.
-        if matches!(from_encoding, "" | "utf8" | "utf-8" | "UTF8" | "UTF-8") {
-            return CodePointString {
-                string: self.string.clone(),
-            };
-        }
-
-        let valid_encoding = shirabe_php_shim::mb_detect_encoding(
-            &self.string,
-            Some(vec![from_encoding.to_string()]),
-            true,
-        )
-        .is_some();
-        // PHP throws InvalidArgumentException. Callers detect `from_encoding` from this very
-        // string, so a mismatch is a programming error.
-        assert!(valid_encoding, "Invalid \"{}\" string.", from_encoding);
-
-        CodePointString {
-            string: shirabe_php_shim::mb_convert_encoding(
-                self.string.clone().into_bytes(),
-                "UTF-8",
-                from_encoding,
-            ),
-        }
-    }
-}