db(core,mig): simplify Statement::bind API and align migrations with DbValue core

- Expose ergonomic Statement::bind overloads (int64, double, bool, string)
- Remove explicit DbValue/str() usage from migration code
- Align FileMigrationsRunner with new ResultSet::row() reference API
- Add ISO-8601 UTC timestamps for applied migrations
- Keep migrations fully SQL-driven and anti-ORM by design

Author: GaspardKirira

include/vix/db/core/Drivers.hpp

@@ -32,6 +32,7 @@ namespace vix::db
     void bind(std::size_t idx, double v) { bind(idx, f64(v)); }
     void bind(std::size_t idx, bool v) { bind(idx, b(v)); }
     void bind(std::size_t idx, std::string v) { bind(idx, str(std::move(v))); }
+    void bind(std::size_t idx, std::string_view v) { bind(idx, std::string(v)); }
     void bindNull(std::size_t idx) { bind(idx, null()); }
     virtual std::unique_ptr<ResultSet> query() = 0;
     virtual std::uint64_t exec() = 0;

include/vix/db/mig/FileMigrationsRunner.hpp

@@ -1,6 +1,6 @@
 /**
  *
- *  @file FileMigrationRunner.hpp
+ *  @file FileMigrationsRunner.hpp
  *  @author Gaspard Kirira
  *
  *  Copyright 2025, Gaspard Kirira.  All rights reserved.

src/mig/FileMigrationsRunner.cpp

@@ -18,12 +18,28 @@
 #include <sstream>
 #include <algorithm>
 #include <unordered_map>
+#include <chrono>
+#include <ctime>
+#include <iomanip>
 
 namespace vix::db
 {
   static std::string now_text()
   {
-    return "now";
+    using namespace std::chrono;
+    const auto now = system_clock::now();
+    const std::time_t t = system_clock::to_time_t(now);
+
+    std::tm tm{};
+#if defined(_WIN32)
+    gmtime_s(&tm, &t);
+#else
+    gmtime_r(&t, &tm);
+#endif
+
+    std::ostringstream oss;
+    oss << std::put_time(&tm, "%Y-%m-%dT%H:%M:%SZ");
+    return oss.str();
   }
 
   void FileMigrationsRunner::ensureTable()
@@ -176,7 +192,7 @@ namespace vix::db
       return false;
 
     if (checksum_out)
-      *checksum_out = rs->row()->getString(0);
+      *checksum_out = rs->row().getString(0);
 
     return true;
   }
@@ -203,7 +219,7 @@ namespace vix::db
     auto rs = st->query();
     if (!rs->next())
       return {};
-    return rs->row()->getString(0);
+    return rs->row().getString(0);
   }
 
   void FileMigrationsRunner::applyAll()