T07: separate a correction from a retarget with a mechanical test

A blanket "no retargeting in the measuring commit" rule would have been
wrong. CB-WP-0002 moved AC-1 three times in exactly that shape and every
move was correct -- each time a new instrument disproved the old figure.
Four legitimate corrections would have been forbidden to catch one bad
retarget.

The test is mechanical rather than a statement of intent:

  correction  the target moves and the implementation does not; legal in
              the same commit provided the instrument's output is there
  retarget    the same commit changes both the target and the code the
              target measures; requires an ADR stating why the new target
              binds on future work

Applied retroactively: AM-4a/AM-4b are UNRATIFIED. They were set after
seeing the measurement, in the commit that produced it, with the
implementation changing too -- a retarget by this test. make dep-weight
is currently enforcing a target no reviewed decision stands behind.
Recorded as an open item; ratifying or changing them is a maintainer
decision, not an implementer's.

Also: specs/InnerLoop.md split into InnerLoop.md (process) and
InnerLoopReference.md (rubric, template, rules, definition of done).
Not a stylistic choice -- `make loop-lint` failed on the commit that
pushed the file to 407 lines against its own ~400 limit. The gate added
this morning to make that rule executable caught its own author within
the hour, which is the cheapest possible demonstration that it works.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

history/260731-inner-loop-rule-audit.md

@@ -134,6 +134,15 @@ evidence files.
   executed cannot be relied on to fire, so it must not be the only defence
   for a class that matters.*
 
+## Open items raised by this audit
+
+- **AM-4a / AM-4b are unratified retargets.** Measured at 246,250 and set
+  at 250,000 in the same commit, by the implementer, with the
+  implementation changing in that commit too — a retarget under the test
+  added to InnerLoop §Step 4 by T07, not a correction. They must be
+  ratified by ADR or changed. Until then `make dep-weight` is enforcing a
+  target no reviewed decision stands behind.
+
 ## Class coverage — where the gaps are
 
 | class | executable rules covering it | assessment |