refactor(generator): remove deterministic speed_profile and hard log_dt clip

These post-processing hacks were added to compensate for small-data
training. With Balabit pretraining they suppress the multimodal
timing distribution and cause the template-y Δt curves seen in the
verify UI.

tests/test_generator.py

@@ -104,3 +104,23 @@ class TestGenerate:
         )
         # 32 move points + 2 click events = 34
         assert len(result) == 34
+
+
+class TestPostProcessing:
+    def test_dt_diversity_preserved(self, model_dir):
+        """After removing speed_profile + median clip, multiple generations
+        should differ in their Δt sequences (not all identical)."""
+        results = [generate(start=(100, 200), end=(500, 400), model_dir=str(model_dir))
+                   for _ in range(5)]
+        # Extract Δt sequences (only move events, not click events)
+        dts = []
+        for r in results:
+            moves = r[:-2]
+            dt_seq = [moves[i+1][2] - moves[i][2] for i in range(len(moves)-1)]
+            dts.append(dt_seq)
+        # At least 2 of the 5 sequences should differ at any given index
+        for i in range(min(len(d) for d in dts)):
+            values = {tuple([d[i]]) for d in dts}
+            if len(values) > 1:
+                return  # at least one position has variation — pass
+        pytest.fail("All 5 Δt sequences are identical at every position — diversity collapsed")