NoisePass now builds branching helper methods (counted int loop,
random arithmetic, even/odd merge, non-throwing ops only) whose
results the entry sums into a private static field, instead of an
empty run()V. Names come from the same NameGenerator styles as
real code and live in a random real package (no more shadow/decoy
uniformity for grep to catch); every generated method gets fresh
StackMapTable frames. weave_first_reachable takes (class, entry)
pairs. New NoiseConfig.junk_methods_per_class (default 3).
Tests assert invariants (unique valid identifiers, calls, field
store, determinism) plus real-JVM verification of junk classes;
paranoid+junk_ratio=1 smoke on lorep: 18 junk classes, all load.
