fix: floor token budgets and surface truncation, add live progress

Reasoning models burn thousands of completion tokens before the
answer. Small per-test caps caused silent truncation and zero scores.
The runner now floors max_tokens at the config default (12000). The
client parses finish_reason. Reports mark truncated cells and the
JSON format carries response text for debugging. A stderr progress
reporter prints one line per completed request; --quiet disables it.

internal/tests/golang_test.go

@@ -119,7 +119,7 @@ func TestGoWorkerPoolTest_Eval(t *testing.T) {
 		want     float64
 	}{
 		{"correct concurrent pool", correctPool, 1},
-		{"sequential pool fails concurrency/timing check", sequentialPool, 0},
+		{"sequential pool fails the maxConcurrent>=2 check", sequentialPool, 0},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {