refactor(pcre): hand back the match instead of copying it out

Preg::match4 and Preg::replace_callback gave callers a
PregMatchedGroups: an IndexMap rebuilt from the match with an owned
String per group, plus a second String for a named group's name key.
That is the copy PregMatches shed when it started wrapping
regex::Captures, reinstated one layer up -- and nearly every regex call
in the tree goes through Preg rather than the shim's preg_* directly, so
almost nothing saw the borrow.

PregMatchedGroups existed only to drop the null (unmatched) groups the
old PregMatches held as Option<String> values. PregMatches::get reports
a non-participating group as None on its own, so the two read alike and
the type collapses into it. Call sites still reach groups through
get(&CaptureKey::ByIndex(N)); what changes is that the value arrives as
a &str borrowed from the subject, which the signatures now carry as a
lifetime.

Three places needed the borrow reckoned with rather than a mechanical
rewrite: PhpFileCleaner::clean and Problem::get_messages read their
groups out before mutating what the match borrows, and
Git::get_authentication_failure names the lifetime of its url argument,
which the result borrows instead of self.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/crates/shirabe/src/util/github.rs b/crates/shirabe/src/util/github.rs
index 9c22a2b3..28a13738 100644
--- a/crates/shirabe/src/util/github.rs
+++ b/crates/shirabe/src/util/github.rs
@@ -326,7 +326,9 @@ impl GitHub {
                 continue;
             }
             if let Some(caps) = Preg::match3(php_regex!(r"{\burl=(?P<url>[^\s;]+)}"), header) {
-                return caps.get(&CaptureKey::ByName("url".to_string())).cloned();
+                return caps
+                    .get(&CaptureKey::ByName("url".to_string()))
+                    .map(str::to_string);
             }
         }