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, 5 insertions, 19 deletions

diff --git a/crates/shirabe/src/package/loader/root_package_loader.rs b/crates/shirabe/src/package/loader/root_package_loader.rs
index 1d068ad6..012c30fd 100644
--- a/crates/shirabe/src/package/loader/root_package_loader.rs
+++ b/crates/shirabe/src/package/loader/root_package_loader.rs
@@ -15,7 +15,7 @@ use crate::repository::RepositoryManager;
 use crate::util::Platform;
 use crate::util::ProcessExecutor;
 use indexmap::IndexMap;
-use shirabe_pcre::{CaptureKey, Preg};
+use shirabe_pcre::Preg;
 use shirabe_php_shim::{
     PhpMixed, RuntimeException, UnexpectedValueException, php_regex, preg_split, strtolower,
 };
@@ -256,14 +256,8 @@ impl RootPackageLoader {
                 php_regex!(r"{(?:^|\| *|, *)([^,\s#|]+)(?:#[^ ]+)? +as +([^,\s|]+)(?:$| *\|| *,)}"),
                 req_version,
             ) {
-                let m1 = m
-                    .get(&CaptureKey::ByIndex(1))
-                    .unwrap_or_default()
-                    .to_string();
-                let m2 = m
-                    .get(&CaptureKey::ByIndex(2))
-                    .unwrap_or_default()
-                    .to_string();
+                let m1 = m.get(1).unwrap_or_default().to_string();
+                let m2 = m.get(2).unwrap_or_default().to_string();
                 let mut alias = IndexMap::new();
                 alias.insert("package".to_string(), strtolower(req_name));
                 alias.insert(
@@ -324,10 +318,7 @@ impl RootPackageLoader {
             for constraint in &constraints {
                 if let Some(m) = Preg::is_match3(&pattern, constraint) {
                     let name = strtolower(req_name);
-                    let m1 = m
-                        .get(&CaptureKey::ByIndex(1))
-                        .unwrap_or_default()
-                        .to_string();
+                    let m1 = m.get(1).unwrap_or_default().to_string();
                     let normalized_m1 = VersionParser::normalize_stability(&m1).unwrap_or_default();
                     let stability = stabilities[normalized_m1.as_str()];
 
@@ -375,12 +366,7 @@ impl RootPackageLoader {
                 && VersionParser::parse_stability(&req_version) == "dev"
             {
                 let name = strtolower(req_name);
-                references.insert(
-                    name,
-                    m.get(&CaptureKey::ByIndex(1))
-                        .unwrap_or_default()
-                        .to_string(),
-                );
+                references.insert(name, m.get(1).unwrap_or_default().to_string());
             }
         }
         references