fix(vision): NaN/inf/bool di uno strumento non diventano più una quota (#16)

runner.run_graph esclude bool e NaN/inf dagli output numerici, con il
motivo in RunOutcome.invalid_outputs. vision_service tratta una quota
mappata con valore None/assente/non finito come "non prodotta" (422),
invece di arrivare a float(None) e sollevare TypeError.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/vision_worker/main.py

@@ -48,6 +48,9 @@ async def run(
         ) from exc
 
     return {
+        # `outcome.outputs` never carries NaN/inf/bool (see runner.run_graph):
+        # a JSON encoder that accepts non-finite floats (Python's stdlib json
+        # does, by default) must never get the chance to emit them here.
         "outputs": outcome.outputs,
         "failures": [
             {"tool_id": f.tool_id, "tool_name": f.tool_name, "error": f.error}
@@ -55,4 +58,5 @@ async def run(
         ],
         "engine_version": outcome.engine_version,
         "duration_ms": outcome.duration_ms,
+        "invalid_outputs": outcome.invalid_outputs,
     }