Feature - Add support for a fiscal year period defined in user settings.

* Add "This fiscal year", "Last fiscal year" as date range options in Transaction Details to filter transactions to those periods
* Add fiscal year ranges to Statistics & Trend Analysis
* Add "fiscal year start date" to user profile settings, allowing the user to select any date of the calendar year as the start of the fiscal year
* Add "fiscal year format" to user profile settings, allowing the user to specify how financial year date labels should appear

Implementation notes:
* The default fiscal year start is January 1 and the default fiscal year display format is "FY 2025"
* Fiscal year start date (month number & day number) are stored together in db as a uint16, high byte & low byte respectively
* February 29 is disallowed as a fiscal year start date, since it is never used as a convention in any country
* Jest is added to the project as a dev dependency, for unit tests in frontend

Signed-off-by: Sebastian Reategui <seb.reategui@gmail.com>

jest.config.ts

@@ -0,0 +1,37 @@
+/**
+ * For a detailed explanation regarding each configuration property, visit:
+ * https://jestjs.io/docs/configuration
+ */
+
+import type { Config } from 'jest';
+
+const config: Config = {
+
+  // Automatically clear mock calls, instances, contexts and results before every test
+  clearMocks: true,
+
+  // Indicates whether the coverage information should be collected while executing the test
+  collectCoverage: false,
+
+  // A map from regular expressions to module names or to arrays of module names that allow to stub out resources with a single module
+  moduleNameMapper: {
+    "^@/(.*)$": "<rootDir>/src/$1"
+  },
+
+  // The test environment that will be used for testing
+  testEnvironment: "node",
+
+  // The glob patterns Jest uses to detect test files
+  testMatch: [
+    "**/__tests__/**/*.[jt]s?(x)",
+    "!**/__tests__/*_gen.[jt]s?(x)"
+  ],
+
+  // A map from regular expressions to paths to transformers
+  transform: {
+    '^.+\\.m?tsx?$': ['ts-jest', { useESM: true, isolatedModules: true }],
+  },
+
+};
+
+module.exports = config;