fix(folio-core): probe schema before create on wasmJs

Wasm SqlDriver doesn't auto-track user_version like the Android
driver, so awaitCreate() ran on every page load and tripped over
already-created tables. Read PRAGMA user_version, run
awaitCreate/awaitMigrate based on it, and self-heal pre-existing
tables with version 0 by stamping the current schema version.

examples/folio/core/src/wasmJsMain/kotlin/app/folio/core/data/DriverFactory.wasmJs.kt

@@ -3,6 +3,7 @@
 package app.folio.core.data
 
 import app.cash.sqldelight.async.coroutines.awaitCreate
+import app.cash.sqldelight.async.coroutines.awaitMigrate
 import app.cash.sqldelight.db.SqlDriver
 import app.cash.sqldelight.driver.worker.WebWorkerDriver
 import app.folio.db.LedgerDatabase
@@ -11,10 +12,59 @@ import org.w3c.dom.Worker
 actual class DriverFactory {
     actual suspend fun create(): SqlDriver {
         val driver = WebWorkerDriver(createSqliteWorker())
-        LedgerDatabase.Schema.awaitCreate(driver)
+        val schema = LedgerDatabase.Schema
+        val current = readUserVersion(driver)
+        val target = schema.version
+        when {
+            current == 0L && !schemaExists(driver) -> {
+                schema.awaitCreate(driver)
+                writeUserVersion(driver, target)
+            }
+            current == 0L -> writeUserVersion(driver, target)
+            current < target -> {
+                schema.awaitMigrate(driver, current, target)
+                writeUserVersion(driver, target)
+            }
+        }
         return driver
     }
 }
 
+private suspend fun readUserVersion(driver: SqlDriver): Long {
+    var version = 0L
+    driver.executeQuery(
+        identifier = null,
+        sql = "PRAGMA user_version",
+        mapper = { cursor ->
+            app.cash.sqldelight.db.QueryResult.AsyncValue {
+                if (cursor.next().await()) version = cursor.getLong(0) ?: 0L
+                Unit
+            }
+        },
+        parameters = 0,
+    ).await()
+    return version
+}
+
+private suspend fun writeUserVersion(driver: SqlDriver, version: Long) {
+    driver.execute(null, "PRAGMA user_version = $version", 0).await()
+}
+
+private suspend fun schemaExists(driver: SqlDriver): Boolean {
+    var exists = false
+    driver.executeQuery(
+        identifier = null,
+        sql = "SELECT name FROM sqlite_master WHERE type = 'table' AND name NOT LIKE 'sqlite_%' LIMIT 1",
+        mapper = { cursor ->
+            app.cash.sqldelight.db.QueryResult.AsyncValue {
+                exists = cursor.next().await()
+                Unit
+            }
+        },
+        parameters = 0,
+    ).await()
+    return exists
+}
+
 private fun createSqliteWorker(): Worker =
     js("""new Worker(new URL("./sqlite.worker.js", import.meta.url), { type: "module" })""")