feat(phase-c): resolve PhpMixed-conversion phase-b TODOs

Implement the foundational PhpMixed conversion infrastructure
(From<bool|i64|f64|String>, order-sensitive PartialEq matching PHP ===)
and resolve the category-G phase-b TODOs that depend on it:

- Fix VCS driver cache paths that discarded parsed JSON or diverged on
  null caches (svn/forgejo/gitlab/git-bitbucket/github).
- Wire up real conversions previously stubbed or dropped: suggests
  platform config, audit ignore-severities, composer_repository search
  and ProviderInfo, class_loader prefix/classmap merges, locker lock
  diff comparison, advisory JSON serialization, SPDX license fields.
- Make GenericRule take a typed ReasonData; populate RULE_ROOT_REQUIRE
  with the constraint and convert PhpMixed at the call sites.

1 files changed, 1 insertions, 1 deletions

diff --git a/crates/shirabe/src/config.rs b/crates/shirabe/src/config.rs
index d6bee9e..e036625 100644
--- a/crates/shirabe/src/config.rs
+++ b/crates/shirabe/src/config.rs
@@ -583,7 +583,7 @@ impl Config {
         self.get_with_flags(key, 0).unwrap_or(PhpMixed::Null)
     }
 
-    // TODO(phase-b): typed convenience; PHP's Config::get() returns mixed.
+    /// Typed convenience accessor for keys whose `get()` value is always a string.
     pub fn get_str(&self, key: &str) -> Result<String> {
         Ok(self
             .get_with_flags(key, 0)?