fix: three errors that ended with the wrong exit code

Found compiling the environment-variable table for AGENTS.md:
- A REVIEW_GATES_MEM_RESERVE_MB that is no number threw
  std::invalid_argument, which nothing caught: the process aborted where
  it should end with a ValueError, exit 1. nan and inf were an unchecked
  cast. They raise ValueError / OverflowError now; a value past int64
  saturates.
- An env file that is not UTF-8: `run` ended with exit 1 where its
  preflight should stop it (exit 3), and `seats` parsed the raw bytes. Both
  read it as strict UTF-8 text now.
- A broker address with a port past 65535 was cut to 16 bits; it is an
  OverflowError now, uncaught (exit 1).

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

implementations/Crafter.Review-Memory.cpp

@@ -20,8 +20,15 @@ namespace Crafter::Review::Memory {
 
     std::int64_t Reserve(const std::optional<std::string>& configured, const fs::path& path) {
         if (configured && !configured->empty()) {
+            // A number, truncated toward zero; ValueError or OverflowError for
+            // what is none. A reserve past int64 saturates: it holds every MB
+            // either way.
             const std::optional<double> value = Dyn::ParseFloat(*configured);
-            if (!value) throw std::invalid_argument(Dyn::FloatError(*configured));
+            if (!value) throw Dyn::Error("ValueError", Dyn::FloatError(*configured));
+            if (std::isnan(*value)) throw Dyn::Error("ValueError", "cannot convert float NaN to integer");
+            if (std::isinf(*value)) throw Dyn::Error("OverflowError", "cannot convert float infinity to integer");
+            if (*value >= 0x1p63) return std::numeric_limits<std::int64_t>::max();
+            if (*value < -0x1p63) return std::numeric_limits<std::int64_t>::min();
             return static_cast<std::int64_t>(*value);
         }
         const std::map<std::string, std::int64_t> info = Platform::MemInfo(path);