test(run): full runs end to end on a claude stand-in

The Runs test drives this binary as crafter-review on a scratch repository,
with a /bin/sh claude that answers every pass from its system file and
prompt: a dry run; a run SIGKILLed in its last gate (every pass goes with
it through its supervisor); the next run resuming the first gate from the
checkpoint, salvaging the killed run's outputs and buying only the pass that
never answered; a run with nothing left to buy; a FIX FIRST with
--no-reuse --no-salvage; a stop by the stop file and by SIGTERM, each
leaving no process behind; a stale stop file dropped by the run that claims
its dir; a stop between gates.

Two fixes it led to:
- A stop that lands while a gate's pool is set up is no longer lost: the
  stop is checked under the same lock that publishes the pool.
- A run never takes the number of a dump on record. Past a killed run that
  left no dump, a later run that bought nothing could have its number
  taken again and its dump written over.

Drivers gains the --no-reuse store check.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

project.cpp

@@ -84,7 +84,7 @@ namespace {
 
     // One per directory under tests/, each an ordinary main() that links the
     // library: exit 0 passes, nonzero fails, 77 skips.
-    constexpr std::array<std::string_view, 23> Tests = {
+    constexpr std::array<std::string_view, 24> Tests = {
         "Crypto",
         "Text",
         "Platform",
@@ -108,6 +108,7 @@ namespace {
         "StoreRules",
         "StacksMemory",
         "ReviewFixes",
+        "Runs",
     };
 
     // The version the binary reports: CI sets it from the tag, a checkout