refactor(preg): split PregMatches reads into get() and name()

PregMatches keyed both forms of a capture group through CaptureKey, so
every read built one: a usize wrapped in an enum, or worse, a String
allocated to name a group that regex::Captures can look up from a &str.
It now mirrors regex::Captures instead -- get() takes the group number,
name() the group name -- and the enum drops out of the type entirely.

That is 285 call sites across 59 files, and the named ones carry most of
the win: `matches.get(&CaptureKey::ByName("host".to_string()))` reads as
`matches.name("host")`. ProcessExecutor loses a `user_key` binding that
existed only to build the key once.

CaptureKey stays as the key type of PregMatchesAll and
PregMatchesAllWithOffsets, where numbered and named entries share one
IndexMap and a key type is the point. Five files still name it.

Also retargets the two preg_match_all comments that described the
occurrence count through `matches[&CaptureKey::ByIndex(0)].len()`, an
Index impl these types no longer carry.

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

1 files changed, 2 insertions, 5 deletions

diff --git a/crates/shirabe/src/downloader/zip_downloader.rs b/crates/shirabe/src/downloader/zip_downloader.rs
index 8ecd131f..b4802066 100644
--- a/crates/shirabe/src/downloader/zip_downloader.rs
+++ b/crates/shirabe/src/downloader/zip_downloader.rs
@@ -8,7 +8,7 @@ use crate::package::PackageInterfaceHandle;
 use crate::util::IniHelper;
 use crate::util::Platform;
 use indexmap::IndexMap;
-use shirabe_pcre::{CaptureKey, Preg};
+use shirabe_pcre::Preg;
 use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{
     CmpOp, ErrorException, PhpMixed, RuntimeException, UnexpectedValueException, ZipArchive,
@@ -116,10 +116,7 @@ impl ZipDownloader {
                 && let Some(m) =
                     Preg::is_match3(php_regex!(r"{^\s*7-Zip(?:\s\[64\])?\s([0-9.]+)}"), &output)
             {
-                let m1 = m
-                    .get(&CaptureKey::ByIndex(1))
-                    .unwrap_or_default()
-                    .to_string();
+                let m1 = m.get(1).unwrap_or_default().to_string();
                 if version_compare(&m1, "21.01", CmpOp::Lt) {
                     self.inner.io.borrow().write_error(&format!(
                         "    <warning>Unzipping using {} {} may result in incorrect file permissions. Install {} 21.01+ or unzip to ensure you get correct permissions.</warning>",