feat: add WELL512-based Random module with seed, float, and int methods

Implement a new `random` module for the Wren language runtime, providing a `Random` class backed by the WELL512a PRNG algorithm. The module supports three seeding strategies (time-based, single numeric seed, and 16-element sequence), generates uniform floats in [0,1) and integers in the full uint32 range, and includes convenience methods for bounded ranges. The implementation adds the C foreign functions `randomAllocate`, `randomSeed0`, `randomSeed1`, `randomSeed16`, `randomFloat`, and `randomInt0`, registers them in the module registry, and includes the Wren wrapper class with constructors accepting no arguments, a number, or a sequence. The commit also adds 12 test scripts covering float/int generation, seeding reproducibility, and error handling for invalid seed types.

test/random/float.wren

@@ -0,0 +1,13 @@
+import "random" for Random
+
+var random = Random.new(12345)
+
+var below = 0
+for (i in 1..1000) {
+  var n = random.float()
+  if (n < 0.5) below = below + 1
+}
+
+// Should be roughly evenly distributed.
+System.print(below > 450) // expect: true
+System.print(below < 550) // expect: true

test/random/float_max.wren

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+import "random" for Random
+
+var random = Random.new(12345)
+
+var below = 0
+for (i in 1..100) {
+  var n = random.float(5)
+  if (n < 0) System.print("too low")
+  if (n >= 5) System.print("too high")
+}

test/random/float_min_max.wren

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+import "random" for Random
+
+var random = Random.new(12345)
+
+var below = 0
+for (i in 1..100) {
+  var n = random.float(2, 5)
+  if (n < 2) System.print("too low")
+  if (n >= 5) System.print("too high")
+}

test/random/int.wren

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+import "random" for Random
+
+var random = Random.new(12345)
+
+var below = 0
+for (i in 1..1000) {
+  var n = random.int()
+  if (n < 2147483648) below = below + 1
+}
+
+// Should be roughly evenly distributed.
+System.print(below > 450) // expect: true
+System.print(below < 550) // expect: true

test/random/int_max.wren

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+import "random" for Random
+
+var random = Random.new(12345)
+
+var counts = [0, 0, 0, 0, 0]
+for (i in 1..10000) {
+  var n = random.int(5)
+  counts[n] = counts[n] + 1
+}
+
+for (count in counts) {
+  if (count < 1900) System.print("too few")
+  if (count > 2100) System.print("too many")
+}

test/random/int_min_max.wren

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+import "random" for Random
+
+var random = Random.new(12345)
+
+var counts = [0, 0, 0, 0, 0, 0, 0, 0]
+for (i in 1..10000) {
+  var n = random.int(3, 8)
+  counts[n] = counts[n] + 1
+}
+
+for (i in 0..2) {
+  if (counts[i] != 0) System.print("too low value")
+}
+
+for (i in 3..7) {
+  if (counts[i] < 1900) System.print("too few")
+  if (counts[i] > 2100) System.print("too many")
+}

test/random/new.wren

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+import "random" for Random
+
+var random = Random.new()
+
+var correct = 0
+for (i in 1..100) {
+  var n = random.float()
+  if (n >= 0) correct = correct + 1
+  if (n < 1) correct = correct + 1
+}
+
+System.print(correct) // expect: 200

test/random/new_empty_sequence.wren

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+import "random" for Random
+
+Random.new([]) // expect runtime error: Sequence cannot be empty.

test/random/new_number.wren

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+import "random" for Random
+
+var random1 = Random.new(123)
+var random2 = Random.new(123)
+
+var correct = 0
+for (i in 1..100) {
+  // Should produce the same values.
+  if (random1.float() == random2.float()) correct = correct + 1
+}
+
+System.print(correct) // expect: 100

test/random/new_sequence.wren

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+import "random" for Random
+
+var random1 = Random.new([1, 2, 3])
+var random2 = Random.new([1, 2, 3])
+
+var correct = 0
+for (i in 1..100) {
+  // Should produce the same values.
+  if (random1.float() == random2.float()) correct = correct + 1
+}
+
+System.print(correct) // expect: 100

test/random/new_wrong_arg_type.wren

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+import "random" for Random
+
+Random.new(false) // expect runtime error: Seed must be a number or a sequence of numbers.

test/random/new_wrong_element_type.wren

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+import "random" for Random
+
+Random.new(["wrong type"]) // expect runtime error: Sequence elements must all be numbers.