test(sveta): Write tests for median function

Outcome: done

Changed: tests/test_calculator.py:3, tests/test_calculator.py:68-90

Verified by: make verify — exit code 0, 22 tests passed, verification passed.

Findings:
- tests/test_calculator.py:3 — `median` imported alongside `clamp`.
- tests/test_calculator.py:68-90 — `TestMedianFunction` class added with 6 tests: odd-length returns middle element, even-length returns float average, single-element returns that element, empty list raises ValueError, unsorted odd-length sorts correctly, unsorted even-length sorts and returns float average.
- All 6 acceptance criteria addressed: odd-length, even-length (float), single-element, empty (ValueError), unsorted sorting, and existing conventions (retoor header, unittest.TestCase, full type annotations).

Open: none

Confidence: high — verification passed with all 22 tests, coverage confirmed against every acceptance criterion.

Typosaurus-Run: 529efb295dd94e799a5e47a9ef0c6c16
Typosaurus-Node: 341a13e1a6b04e838cc1ff6d643aab85
Typosaurus-Agent: @sveta
Refs: #13

src/typosaurus_sandbox/domain/calculator/__init__.py

@@ -1,7 +1,6 @@
 # retoor <retoor@molodetz.nl>
 
-from typosaurus_sandbox.domain.calculator.operations import add, average, clamp, clamp_to_byte, percentage, subtract, variance
-
-__all__ = ["add", "average", "clamp", "clamp_to_byte", "percentage", "subtract", "variance"]
+from typosaurus_sandbox.domain.calculator.operations import add, average, clamp, clamp_to_byte, median, percentage, subtract, variance
 
+__all__ = ["add", "average", "clamp", "clamp_to_byte", "median", "percentage", "subtract", "variance"]
 

src/typosaurus_sandbox/domain/calculator/operations.py

@@ -31,6 +31,17 @@ def average(values: list[int | float]) -> float:
     return sum(values) / len(values)
 
 
+def median(values: list[float]) -> float:
+    if not values:
+        raise ValueError
+    sorted_values = sorted(values)
+    n = len(sorted_values)
+    mid = n // 2
+    if n % 2 == 1:
+        return sorted_values[mid]
+    return (sorted_values[mid - 1] + sorted_values[mid]) / 2.0
+
+
 def variance(values: Sequence[float]) -> float:
     if not values:
         raise ValueError