Final revision: audit fixes, cross-scheme comparisons, known-plaintext stage

- exclude the all-ones Walsh-Hadamard row and test every key family
  against the all-ones guess
- pass the model dimension to the noise scaling so the key-length sweep
  runs at a fixed per-dimension SNR
- known-plaintext attack with nested accumulation and common random
  numbers, averaged over 40 collections
- key sensitivity and brute-force search extended to the permutation
  key and the index cipher
- make_tables regenerates all three result tables from the CSVs

data/sec_regjam.csv

@@ -1,8 +1,8 @@
 jsr_db,plain,regularized
--10,0.46879,0.4691633333
--5,0.6335366667,0.6307333333
-0,0.8056466667,0.8018166667
-5,0.9187366667,0.91602
-10,0.9708533333,0.9693866667
-15,0.9902133333,0.9896433333
-20,0.9967333333,0.9965933333
+-10,0.46703,0.4719866667
+-5,0.6348,0.6301533333
+0,0.8073133333,0.80122
+5,0.9191366667,0.91577
+10,0.9707266667,0.96911
+15,0.9901433333,0.99006
+20,0.9968333333,0.9964333333