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, 4 insertions, 10 deletions

diff --git a/crates/shirabe/src/command/package_discovery_trait.rs b/crates/shirabe/src/command/package_discovery_trait.rs
index 5b53bcbd..d31b5894 100644
--- a/crates/shirabe/src/command/package_discovery_trait.rs
+++ b/crates/shirabe/src/command/package_discovery_trait.rs
@@ -19,7 +19,7 @@ use crate::repository::RepositorySet;
 use crate::repository::{RepositoryInterface, SearchResult};
 use crate::util::Filesystem;
 use indexmap::IndexMap;
-use shirabe_pcre::{CaptureKey, Preg};
+use shirabe_pcre::Preg;
 use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{
     Exception, InvalidArgumentException, LogicException, PHP_EOL, PhpMixed, array_keys,
@@ -334,27 +334,21 @@ pub trait PackageDiscoveryTrait: BaseCommand {
                                 php_regex!(r"{^\s*(?P<name>[\S/]+)(?:\s+(?P<version>\S+))?\s*$}"),
                                 &selection,
                             ) {
-                                if let Some(v) = m
-                                    .get(&CaptureKey::ByName("version".to_string()))
-                                    .map(str::to_string)
-                                {
+                                if let Some(v) = m.name("version").map(str::to_string) {
                                     // parsing `acme/example ~2.3`
                                     // validate version constraint
                                     version_parser_clone.parse_constraints(&v)?;
 
                                     return Ok(PhpMixed::String(format!(
                                         "{} {}",
-                                        m.get(&CaptureKey::ByName("name".to_string()))
-                                            .unwrap_or_default(),
+                                        m.name("name").unwrap_or_default(),
                                         v,
                                     )));
                                 }
 
                                 // parsing `acme/example`
                                 return Ok(PhpMixed::String(
-                                    m.get(&CaptureKey::ByName("name".to_string()))
-                                        .unwrap_or_default()
-                                        .to_string(),
+                                    m.name("name").unwrap_or_default().to_string(),
                                 ));
                             }