chore: reorganize test files into domain-specific subdirectories

- Moved unit tests for user authentication into `tests/unit/auth/`
- Relocated integration tests for payment processing to `tests/integration/payments/`
- Grouped API endpoint tests under `tests/api/` with separate files for each resource
- Updated test runner configuration to discover tests in new directory structure

test/method/arity.wren

@@ -0,0 +1,26 @@
+class Foo {
+  method { 0 }
+  method(a) { a }
+  method(a, b) { a + b }
+  method(a, b, c) { a + b + c }
+  method(a, b, c, d) { a + b + c + d }
+  method(a, b, c, d, e) { a + b + c + d + e }
+  method(a, b, c, d, e, f) { a + b + c + d + e + f }
+  method(a, b, c, d, e, f, g) { a + b + c + d + e + f + g }
+  method(a, b, c, d, e, f, g, h) { a + b + c + d + e + f + g + h }
+  method(a, b, c, d, e, f, g, h, i) { a + b + c + d + e + f + g + h + i }
+  method(a, b, c, d, e, f, g, h, i, j) { a + b + c + d + e + f + g + h + i + j }
+}
+
+var foo = Foo.new
+io.write(foo.method) // expect: 0
+io.write(foo.method(1)) // expect: 1
+io.write(foo.method(1, 2)) // expect: 3
+io.write(foo.method(1, 2, 3)) // expect: 6
+io.write(foo.method(1, 2, 3, 4)) // expect: 10
+io.write(foo.method(1, 2, 3, 4, 5)) // expect: 15
+io.write(foo.method(1, 2, 3, 4, 5, 6)) // expect: 21
+io.write(foo.method(1, 2, 3, 4, 5, 6, 7)) // expect: 28
+io.write(foo.method(1, 2, 3, 4, 5, 6, 7, 8)) // expect: 36
+io.write(foo.method(1, 2, 3, 4, 5, 6, 7, 8, 9)) // expect: 45
+io.write(foo.method(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)) // expect: 55

test/method/operators.wren

@@ -0,0 +1,31 @@
+class Foo {
+  + other { "infix + " + other }
+  - other { "infix - " + other }
+  * other { "infix * " + other }
+  / other { "infix / " + other }
+  % other { "infix % " + other }
+  < other { "infix < " + other }
+  > other { "infix > " + other }
+  <= other { "infix <= " + other }
+  >= other { "infix >= " + other }
+  == other { "infix == " + other }
+  != other { "infix != " + other }
+
+  ! { "prefix !" }
+  - { "prefix -" }
+}
+
+var foo = Foo.new
+io.write(foo + "a") // expect: infix + a
+io.write(foo - "a") // expect: infix - a
+io.write(foo * "a") // expect: infix * a
+io.write(foo / "a") // expect: infix / a
+io.write(foo % "a") // expect: infix % a
+io.write(foo < "a") // expect: infix < a
+io.write(foo > "a") // expect: infix > a
+io.write(foo <= "a") // expect: infix <= a
+io.write(foo >= "a") // expect: infix >= a
+io.write(foo == "a") // expect: infix == a
+io.write(foo != "a") // expect: infix != a
+io.write(!foo) // expect: prefix !
+io.write(-foo) // expect: prefix -

test/method/static.wren

@@ -0,0 +1,13 @@
+class Foo {
+  bar { "on instance" }
+  static bar { "on metaclass" }
+
+  bar(arg) { "on instance " + arg }
+  static bar(arg) { "on metaclass " + arg }
+}
+
+io.write("on metaclass " + "arg") // expect: on metaclass arg
+io.write(Foo.new.bar)        // expect: on instance
+io.write(Foo.bar)            // expect: on metaclass
+io.write(Foo.new.bar("arg")) // expect: on instance arg
+io.write(Foo.bar("arg"))     // expect: on metaclass arg