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, 0 insertions, 3 deletions

diff --git a/crates/shirabe/src/command/update_command.rs b/crates/shirabe/src/command/update_command.rs
index f0dc830..4fe9b6a 100644
--- a/crates/shirabe/src/command/update_command.rs
+++ b/crates/shirabe/src/command/update_command.rs
@@ -655,9 +655,6 @@ impl UpdateCommand {
             .into());
         }
 
-        // TODO(phase-b): IOInterface::select returns PhpMixed and takes
-        // Vec<String> choices; convert IndexMap<String, String> autocompleter values
-        // to choices and downcast PhpMixed back to Vec<String>.
         let select_result = io.select(
             "Select packages: (Select more than one value separated by comma) ".to_string(),
             autocompleter_values