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, 5 deletions

diff --git a/crates/shirabe/src/command/update_command.rs b/crates/shirabe/src/command/update_command.rs
index 5c119489..e9f0e3ce 100644
--- a/crates/shirabe/src/command/update_command.rs
+++ b/crates/shirabe/src/command/update_command.rs
@@ -27,7 +27,7 @@ use crate::repository::PlatformRepository;
 use crate::repository::RepositorySet;
 use crate::util::HttpDownloader;
 use indexmap::IndexMap;
-use shirabe_pcre::{CaptureKey, Preg};
+use shirabe_pcre::Preg;
 use shirabe_php_shim::{
     InvalidArgumentException, PhpMixed, RuntimeException, array_filter, array_intersect,
     array_keys, array_merge_map, array_search_in_vec, impl_php_class, php_regex, strtolower,
@@ -464,10 +464,8 @@ impl Command for UpdateCommand {
                 let Some(matches) = matches else {
                     continue;
                 };
-                let constraint = parser.parse_constraints(&format!(
-                    "~{}",
-                    matches.get(&CaptureKey::ByIndex(1)).unwrap_or_default()
-                ))?;
+                let constraint = parser
+                    .parse_constraints(&format!("~{}", matches.get(1).unwrap_or_default()))?;
                 if let Some(existing) = temporary_constraints.get(&package.get_name()) {
                     temporary_constraints.insert(
                         package.get_name(),