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, 3 insertions, 6 deletions

diff --git a/crates/shirabe/src/command/show_command.rs b/crates/shirabe/src/command/show_command.rs
index b479c9a8..4be7873c 100644
--- a/crates/shirabe/src/command/show_command.rs
+++ b/crates/shirabe/src/command/show_command.rs
@@ -36,7 +36,7 @@ use crate::repository::RepositoryUtils;
 use crate::repository::RootPackageRepository;
 use crate::util::PackageInfo;
 use indexmap::IndexMap;
-use shirabe_pcre::{CaptureKey, Preg};
+use shirabe_pcre::Preg;
 use shirabe_php_shim::{
     CmpOp, DATE_ATOM, InvalidArgumentException, LogicException, PhpMixed, UnexpectedValueException,
     array_search, date_format_to_strftime, date_local, extension_loaded, impl_php_class,
@@ -1378,12 +1378,9 @@ impl ShowCommand {
                     &package.get_version(),
                 )
             {
-                let zero_major = groups
-                    .get(&CaptureKey::ByName("zero_major".to_string()))
-                    .unwrap_or_default()
-                    .to_string();
+                let zero_major = groups.name("zero_major").unwrap_or_default().to_string();
                 let first_meaningful = groups
-                    .get(&CaptureKey::ByName("first_meaningful".to_string()))
+                    .name("first_meaningful")
                     .unwrap_or_default()
                     .to_string()
                     .parse::<i64>()