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/service_inventory.bats

@@ -125,8 +125,8 @@ PYEOF
 }
 
 @test "inventory: the node-exporter unit is a per-host rendered template" {
-    # Rank 6: the two node-exporter quadlets were a MIRROR pair kept in
-    # step by a comment. The render is now the law on both hosts.
+    # Both quadlets are rendered artifacts: the render — not a hand-edited
+    # mirror kept in step by a comment — defines the unit on every host.
     for host in dankclaw dankserver; do
         run bash -c "cd '$REPO_ROOT' && python3 scripts/service-map.py render node-exporter-unit --host $host | \
             diff -u $host/observability/quadlet/node-exporter.container -"