Finalize Dexie-to-SQLite migration prep: docs, circular dep removal, SQL helpers, tests

- Removed all vestigial Dexie/USE_DEXIE_DB references from code and docs
- Centralized DB logic in PlatformServiceMixin; resolved logger/databaseUtil circular dependency
- Modularized SQL helpers (`$generateInsertStatement`, `$generateUpdateStatement`) and added unit tests
- Created/updated migration tracking docs and helper script for cross-machine progress
- Confirmed all lint/type checks and tests pass; ready for systematic file migration

src/utils/sqlHelpers.ts

@@ -0,0 +1,67 @@
+/**
+ * SQL Statement Generation Helpers
+ * Provides utility functions for generating parameterized SQL INSERT and UPDATE statements.
+ *
+ * Author: Matthew Raymer
+ */
+
+/**
+ * Generates SQL INSERT statement and parameters from a model object
+ * @param model - The object to insert
+ * @param tableName - The table name
+ * @returns { sql, params } - SQL string and parameter array
+ */
+export function generateInsertStatement(
+  model: Record<string, unknown>,
+  tableName: string,
+): { sql: string; params: unknown[] } {
+  const columns = Object.keys(model).filter((key) => model[key] !== undefined);
+  const values = Object.values(model)
+    .filter((value) => value !== undefined)
+    .map((value) => {
+      if (value === null || value === undefined) return null;
+      if (typeof value === "object" && value !== null) {
+        return JSON.stringify(value);
+      }
+      if (typeof value === "boolean") return value ? 1 : 0;
+      return value;
+    });
+  const placeholders = values.map(() => "?").join(", ");
+  const insertSql = `INSERT INTO ${tableName} (${columns.join(", ")}) VALUES (${placeholders})`;
+  return { sql: insertSql, params: values };
+}
+
+/**
+ * Generates SQL UPDATE statement and parameters from a model object
+ * @param model - The object with fields to update
+ * @param tableName - The table name
+ * @param whereClause - The WHERE clause (e.g. "id = ?")
+ * @param whereParams - Parameters for the WHERE clause
+ * @returns { sql, params } - SQL string and parameter array
+ */
+export function generateUpdateStatement(
+  model: Record<string, unknown>,
+  tableName: string,
+  whereClause: string,
+  whereParams: unknown[] = [],
+): { sql: string; params: unknown[] } {
+  const setClauses: string[] = [];
+  const params: unknown[] = [];
+  Object.entries(model).forEach(([key, value]) => {
+    setClauses.push(`${key} = ?`);
+    let convertedValue = value ?? null;
+    if (convertedValue !== null) {
+      if (typeof convertedValue === "object") {
+        convertedValue = JSON.stringify(convertedValue);
+      } else if (typeof convertedValue === "boolean") {
+        convertedValue = convertedValue ? 1 : 0;
+      }
+    }
+    params.push(convertedValue);
+  });
+  if (setClauses.length === 0) {
+    throw new Error("No valid fields to update");
+  }
+  const sql = `UPDATE ${tableName} SET ${setClauses.join(", ")} WHERE ${whereClause}`;
+  return { sql, params: [...params, ...whereParams] };
+}