refact(comments): state the mechanism, not the incident

Every comment that invoked a 'law' (50 word-boundary sites across 28
tracked files) now states what is going on and why, in terms that
transfer to any project: gate twins drift until one side greenlights
what the other refuses; a tag re-points while a digest pins; a
restrictive engine behavior belongs to the runtime that imposed it and
must be re-tested, not inherited; a speculative head is tensors in the
file, not a flag; snapshot links dangle where the container resolves
them; exit 0 is a clean stop to systemd, so a self-exiting daemon on
on-failure goes dark reporting success. Event narratives and dates are
gone from these comments; the mechanics carry the argument.

Behavior-identical: bash -n, py_compile, yaml parse, full bats suite
408/408 green. One symbol rename rides along (stack script local
scale_law -> scale_contract, with its log text).

tests/frank_dragoon_unit.bats

@@ -10,11 +10,11 @@
 # exact strings the engine reads: the image DIGEST, the checkpoint/n-gram/
 # vision file names AND byte counts inside the /models mount, and the
 # tokenizer's flat-file shape (a HF cache snapshot's symlinks dangle inside
-# the container). A serve gate and a deployer gate that disagree is the
-# 2026-10-01 crash-loop; both sides are pinned here, plus the one engine
-# law the card is emphatic about: HALOGEN_SPEC_ADAPT=0 — the default
-# adaptive policy silently disables the MTP head per request and HALVES
-# decode.
+# the container). A serve gate and a deployer gate that disagree let a
+# deploy pass what the unit would refuse, so both sides are pinned here —
+# plus the one engine behavior the card is emphatic about:
+# HALOGEN_SPEC_ADAPT=0 — the default adaptive policy silently disables the
+# MTP head per request and HALVES decode.
 #
 # Everything is tested from what an operator or supervisor can observe —
 # the command line podman would run, the exit code, the deployer's error
@@ -117,10 +117,11 @@ good_env() {
 
 @test "the head stays on: adaptive spec must stay 0 and the window shape pinned" {
     # The card is emphatic: the default adaptive policy turns the MTP head
-    # off for whole requests after low acceptance and HALVES decode. The
-    # two-slot law does NOT carry over from the 27B engine — on this line
-    # batching and speculation coexist (the card's quickstart ships 2
-    # slots WITH the head), so 2 is concurrent capacity, not a tax.
+    # off for whole requests after low acceptance and HALVES decode. A
+    # "slots > 1 disables drafting" restriction belongs to the engine
+    # generation that imposed it — on this line batching and speculation
+    # coexist (the card's quickstart ships 2 slots WITH the head), so 2 is
+    # concurrent capacity, not a tax.
     grep -qE '^HALOGEN_SPEC_ADAPT=0$' "$ENV_FILE"
     grep -qE '^HALOGEN_KV_SLOTS=2$' "$ENV_FILE"
     # The cap/timeout pair is coupled (FLAGS.md table): a request at the
@@ -186,7 +187,7 @@ good_env() {
 
 @test "the serve script refuses a checkpoint of the wrong byte count" {
     # A truncated curl exit-0 artifact must not boot; the Hub's byte
-    # count is the contract (fleet fetch law).
+    # count is the contract, any other size is a broken artifact.
     podman_stub
     good_env
     run env PATH="$TEST_TMP/bin:$PATH" "${GOOD_ENV[@]}" \
@@ -287,16 +288,16 @@ $(cat "$TEST_TMP/serve.log")"
     ! grep -q 'PODMAN wait' "$TEST_TMP/serve.log"
 }
 
-@test "the shipped env keeps the harness fit law inside the ceiling" {
+@test "the shipped env keeps the harness fit margin inside the ceiling" {
     # 262144 (the checkpoint's native window) is the per-slot hard ceiling
     # (a longer prompt is a 400 naming the limit, never a silent
     # truncation). The harness clamps max_tokens = min(45056, 217088 − est
     # − 4096), compacts at 85 % of its declared 217088 window, and its
     # chars/4 est UNDER-counts the rendered prompt by ~3 % on code/agent
-    # traffic (measured 4,450 tokens at est 152,938 on 2026-10-07 — with
-    # window == ceiling, every request over ~146k est was a guaranteed
-    # 400 before compaction could fire at 85 %). The 45k gap between the
-    # harness window and the engine ceiling must absorb that error at
+    # traffic — so a harness window equal to the engine ceiling would make
+    # every long request a guaranteed 400 before compaction could fire.
+    # The 45k gap between the harness window and the engine ceiling must
+    # absorb that error at
     # both monotone maxima of est + budget (est ≤ 217088 − 4096):
     #   full budget at the compaction threshold: 1.03*184524 + 45056
     #   clamped budget at the clamp's zero point: 1.03*212992 + 0