Fix cross-platform compilation and API compatibility

- Resolved type compatibility issues between macOS and Linux
- Fixed get_loop_recommendations function return type (string vs bytes)
- Used mixed types approach for getDynamicCarbsOnBoard (Double for carbRatio, LoopQuantity for ISF)
- 15/16 tests now pass on macOS (only getDynamicCarbsOnBoard has remaining unit conversion issue)

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: miriamkw

Sources/LoopAlgorithmToPython/LoopAlgorithmToPython.swift

@@ -438,9 +438,9 @@ public func getDynamicCarbsOnBoard(jsonData: UnsafePointer<Int8>?) -> Double {
         let startDate = dateFormatter.date(from: input.inputICE[0].startAt)!
         let endDate = dateFormatter.date(from: input.inputICE.last!.startAt)!
 
-        // Create schedule values with Double values as expected by the function
+        // Mixed types: Double for carbRatio, LoopQuantity for ISF (as required by API)
         let carbRatio = [AbsoluteScheduleValue(startDate: startDate, endDate: endDate, value: input.carbRatio)]
-        let isf = [AbsoluteScheduleValue(startDate: startDate, endDate: endDate, value: input.sensitivity)]
+        let isf = [AbsoluteScheduleValue(startDate: startDate, endDate: endDate, value: LoopQuantity(unit: LoopUnit(from: "mg/dL"), doubleValue: input.sensitivity))]
 
         let statuses = [carbEntries[0]].map(
             to: inputICE,

loop_to_python_api/api.py

@@ -148,7 +148,8 @@ def get_loop_recommendations(json_file, len=72):
     swift_lib.getLoopRecommendations.argtypes = [ctypes.c_char_p]
     swift_lib.getLoopRecommendations.restype = ctypes.c_char_p
 
-    return swift_lib.getLoopRecommendations(json_bytes)
+    result = swift_lib.getLoopRecommendations(json_bytes).decode('utf-8')
+    return result
 
 def add_insulin_counteraction_effect_to_df(df, basal, isf, cr, insulin_type='novolog', batch_size=300, overlap=72):
     """