db: Add profile-mode timings of load at startup

As we add more features using the database and more queries we make
from it here at the app's startup, this will help us check that we
aren't unduly delaying startup.

Results on my Pixel 8, with 2 account records:

db load time 91.9ms total: 1.5ms init, 85.4ms settings, 5.0ms accounts
db load time 87.8ms total: 1.7ms init, 78.1ms settings, 8.0ms accounts
db load time 93.3ms total: 1.2ms init, 83.7ms settings, 8.5ms accounts
db load time 78.1ms total: 1.4ms init, 71.8ms settings, 4.8ms accounts
db load time 86.9ms total: 1.2ms init, 77.8ms settings, 7.9ms accounts

Author: gnprice

lib/model/store.dart

@@ -882,9 +882,27 @@ class LiveGlobalStore extends GlobalStore {
   // We keep the API simple and synchronous for the bulk of the app's code
   // by doing this loading up front before constructing a [GlobalStore].
   static Future<GlobalStore> load() async {
+    // Loading this data takes roughly 80-100ms (measured on a Pixel 8).
+    // That's only a small increment on the time spent loading server data,
+    // so we don't worry about optimizing it further.
+    // In a future where we keep server data locally between runs (#477) --
+    // which will also mean having much more data to load from the database --
+    // we'd invest in this area more.  For example we'd try doing these
+    // in parallel, or deferring some to be concurrent with loading server data.
+    final stopwatch = Stopwatch()..start();
     final db = AppDatabase(NativeDatabase.createInBackground(await _dbFile()));
+    final t1 = stopwatch.elapsed;
     final globalSettings = await db.getGlobalSettings();
+    final t2 = stopwatch.elapsed;
     final accounts = await db.select(db.accounts).get();
+    final t3 = stopwatch.elapsed;
+    if (kProfileMode) {
+      String format(Duration d) =>
+        "${(d.inMicroseconds / 1000.0).toStringAsFixed(1)}ms";
+      profilePrint("db load time ${format(t3)} total: ${format(t1)} init, "
+        "${format(t2 - t1)} settings, ${format(t3 - t2)} accounts");
+    }
+
     return LiveGlobalStore._(
       backend: LiveGlobalStoreBackend._(db: db),
       globalSettings: globalSettings,