Bump version to 0.19.0

Author: grega

bench/results.csv

@@ -75,3 +75,7 @@ timestamp,version,machine,fixture,lines,median_ms
 2026-03-22T22:16:45Z,0.18.5,Apple_M1_Pro_8c,medium,164,48.9
 2026-03-22T22:16:45Z,0.18.5,Apple_M1_Pro_8c,large,439,104.1
 2026-03-22T22:16:45Z,0.18.5,Apple_M1_Pro_8c,stress,561,114.9
+2026-03-23T21:18:18Z,0.19.0,Apple_M1_Pro_8c,small,21,21.1
+2026-03-23T21:18:18Z,0.19.0,Apple_M1_Pro_8c,medium,164,49.2
+2026-03-23T21:18:18Z,0.19.0,Apple_M1_Pro_8c,large,439,103.3
+2026-03-23T21:18:18Z,0.19.0,Apple_M1_Pro_8c,stress,561,114.7