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, 9 deletions

diff --git a/crates/shirabe/src/dependency_resolver/problem.rs b/crates/shirabe/src/dependency_resolver/problem.rs
index 63561e98..c42caa35 100644
--- a/crates/shirabe/src/dependency_resolver/problem.rs
+++ b/crates/shirabe/src/dependency_resolver/problem.rs
@@ -10,7 +10,7 @@ use crate::repository::LockArrayRepository;
 use crate::repository::PlatformRepository;
 use crate::repository::RepositorySet;
 use indexmap::IndexMap;
-use shirabe_pcre::{CaptureKey, Preg};
+use shirabe_pcre::Preg;
 use shirabe_php_shim::{
     CmpOp, LogicException, PhpMixed, extension_loaded, implode, loosely_compare, php_regex,
     spl_object_hash, sprintf, str_replace, stripos, strpos, strtolower, substr, substr_count,
@@ -234,14 +234,8 @@ impl Problem {
                 None
             };
             if let Some(m) = matched {
-                let pkg_key = m
-                    .get(&CaptureKey::ByIndex(1))
-                    .unwrap_or_default()
-                    .to_string();
-                let m2 = m
-                    .get(&CaptureKey::ByIndex(2))
-                    .unwrap_or_default()
-                    .to_string();
+                let pkg_key = m.get(1).unwrap_or_default().to_string();
+                let m2 = m.get(2).unwrap_or_default().to_string();
                 message = str_replace("%", "%%", &message);
                 let template = Preg::replace(php_regex!(r"{^\S+ \S+ }"), "%s%s ", &message);
                 messages.push(template.clone());