HeadOn (no-lead) vs Pattern LIVE at long range: clean negative, offline ruler killed

2 arms x 15 runs x 7 rounds, one frozen binary from HEAD a82c864, real DrussGT,
server-side events sidecar. Shipped rack is onlyPattern, so control=Pattern-only
and headon=HeadOn-only (TR_RACK_PATTERN=off TR_RACK_HEADON=both).

  arm      dmg/run  dmgtk/run  round wins  shots/run
  control      279        211     48/105       785
  headon        14        228      0/105       580

Round wins and dmg/run both separate at p<0.0001 (MC permutation, se 0.0000),
~7x the damage MDE (35.8). Per range band (pooled, 15 runs):
  300-450: Pattern 12.3% (4590 shots) vs HeadOn 0.6% (3701)  p<0.0001, MDE 2.0pp
  450+   : Pattern  9.2% (6671)       vs HeadOn 0.4% (4177)  p<0.0001, MDE 1.1pp
HeadOn loses EVERY long-range band by 20-23x, so the whole-battle loss is not a
close-range artefact.

The offline ruler (prediction_quality_results.txt) predicted the opposite: HeadOn
meanAbs 14.61 vs Pattern 17.53 at 300-450 and 12.33 vs 16.19 at 450+, hitProxy
.105/.104 and .098/.077 (+27%). That is an open-loop replay of a FIXED enemy
track, so it cannot see that a different bullet makes the surfer dodge
differently; live, the static gun does not lead at all.

TR_PATTERN_RAD_SCALE arms were skipped: applyRadial scales aim DISTANCE along an
unchanged bearing, so it cannot express 'less lead' (bearing is what firing uses).
HeadOn confirmed to ignore bulletSpeed (head_on.nim:9), liveness OK 15/15.

Adds the range-band analyzer tools/ab/ab_range_bands.py (reuses the lead-capture
Run alignment) and the captured fixtures. Does not touch bitbrain_gun.nim /
bitbrain_campaign.md (job-100).

common_libs/tests/fixtures/headon_longrange_live_results.json

@@ -0,0 +1,199 @@
+{
+ "arms": {
+  "control": {
+   "bands_pooled": {
+    "0-100": {
+     "hits": 2,
+     "shots": 3
+    },
+    "100-200": {
+     "hits": 4,
+     "shots": 28
+    },
+    "200-300": {
+     "hits": 26,
+     "shots": 211
+    },
+    "300-450": {
+     "hits": 565,
+     "shots": 4590
+    },
+    "450+": {
+     "hits": 616,
+     "shots": 6671
+    },
+    "ALL": {
+     "hits": 1213,
+     "shots": 11503
+    }
+   },
+   "runs": {
+    "run1.jsonl": {
+     "hits": 81,
+     "shots": 781
+    },
+    "run10.jsonl": {
+     "hits": 90,
+     "shots": 819
+    },
+    "run11.jsonl": {
+     "hits": 78,
+     "shots": 822
+    },
+    "run12.jsonl": {
+     "hits": 80,
+     "shots": 781
+    },
+    "run13.jsonl": {
+     "hits": 85,
+     "shots": 754
+    },
+    "run14.jsonl": {
+     "hits": 78,
+     "shots": 811
+    },
+    "run15.jsonl": {
+     "hits": 62,
+     "shots": 628
+    },
+    "run2.jsonl": {
+     "hits": 92,
+     "shots": 750
+    },
+    "run3.jsonl": {
+     "hits": 90,
+     "shots": 751
+    },
+    "run4.jsonl": {
+     "hits": 67,
+     "shots": 761
+    },
+    "run5.jsonl": {
+     "hits": 88,
+     "shots": 830
+    },
+    "run6.jsonl": {
+     "hits": 72,
+     "shots": 725
+    },
+    "run7.jsonl": {
+     "hits": 86,
+     "shots": 731
+    },
+    "run8.jsonl": {
+     "hits": 77,
+     "shots": 774
+    },
+    "run9.jsonl": {
+     "hits": 87,
+     "shots": 785
+    }
+   }
+  },
+  "headon": {
+   "bands_pooled": {
+    "0-100": {
+     "hits": 0,
+     "shots": 1
+    },
+    "100-200": {
+     "hits": 8,
+     "shots": 97
+    },
+    "200-300": {
+     "hits": 12,
+     "shots": 469
+    },
+    "300-450": {
+     "hits": 21,
+     "shots": 3701
+    },
+    "450+": {
+     "hits": 15,
+     "shots": 4177
+    },
+    "ALL": {
+     "hits": 56,
+     "shots": 8445
+    }
+   },
+   "runs": {
+    "run1.jsonl": {
+     "hits": 2,
+     "shots": 590
+    },
+    "run10.jsonl": {
+     "hits": 6,
+     "shots": 604
+    },
+    "run11.jsonl": {
+     "hits": 5,
+     "shots": 550
+    },
+    "run12.jsonl": {
+     "hits": 2,
+     "shots": 522
+    },
+    "run13.jsonl": {
+     "hits": 4,
+     "shots": 616
+    },
+    "run14.jsonl": {
+     "hits": 3,
+     "shots": 584
+    },
+    "run15.jsonl": {
+     "hits": 4,
+     "shots": 549
+    },
+    "run2.jsonl": {
+     "hits": 3,
+     "shots": 561
+    },
+    "run3.jsonl": {
+     "hits": 1,
+     "shots": 552
+    },
+    "run4.jsonl": {
+     "hits": 6,
+     "shots": 570
+    },
+    "run5.jsonl": {
+     "hits": 4,
+     "shots": 567
+    },
+    "run6.jsonl": {
+     "hits": 3,
+     "shots": 520
+    },
+    "run7.jsonl": {
+     "hits": 8,
+     "shots": 605
+    },
+    "run8.jsonl": {
+     "hits": 5,
+     "shots": 588
+    },
+    "run9.jsonl": {
+     "hits": 0,
+     "shots": 467
+    }
+   }
+  }
+ },
+ "band_labels": [
+  "0-100",
+  "100-200",
+  "200-300",
+  "300-450",
+  "450+"
+ ],
+ "session": {
+  "binary_sha256": "9d20f530d633982b30735d5ece38da09b707737ae1c57238ee41abe928276601",
+  "commit": "a82c864c6075d8325589681bae23b371e3c4f1b5",
+  "conc": 8,
+  "rounds": 7,
+  "runs": 15,
+  "timestamp": "2026-09-24T23:45:01+02:00"
+ }
+}