Route by job, not by file size: the tool table fresh sessions needed

Oliver's concern, after the un-chunking: a fresh session walked straight into
_regen.py and diagnosed from there, twice — first the legacy prompts, then the
model's rolls — while the real bug sat in the cutter, provable by putting any
fam_ sheet next to the sprite cut from it. The family-pipeline section already
demoted _regen.py, but 270 lines below the "Asset pipeline" heading, and the
session memory that routed the last investigation pointed at _regen by name.

So the routing is now the FIRST thing under "## Asset pipeline": a
which-tool-for-which-job table that names _famroll -> _zsheet for families,
marks _regen.py as the single-sheet remaster tool it still is (bosses, players,
crowd, weapons — those jobs keep it alive, so it stays), and states the
diagnostic rule that would have saved two days: when installed art looks worse
than the _refcheck sheet it came from, the suspect is the CUT, and a re-cut is
free. _regen.py's own header says the same, for whoever opens it first anyway.

The "Only ink votes" lesson joins the family-pipeline section with the numbers:
0.0% of ink blocks uniform at b=11 against 99.2% of empty ones is how a
detector proven on single-row sheets quietly broke on 9-row geometry — the
threshold never changed, the data under it did.

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

assets/_regen.py

@@ -1,5 +1,11 @@
 # _regen.py — redraw a batch of sprites at real pixel-art resolution, end to end.
 #
+# ROUTING — CHECK BEFORE USING. This is the SINGLE-SHEET remaster tool (boss roster, players, crowd,
+# weapons — anything without a family). A whole opponent family is NEVER built here: that is
+# _famroll.py -> _zsheet.py (PROJECT.md, "THE ZOMBIE FAMILY PIPELINE"), because nine separate rolls
+# is nine chances for the character to drift, and it took every one of them. See PROJECT.md
+# "WHICH TOOL FOR WHICH JOB" for the full routing table.
+#
 #   python3 assets/_regen.py shambler_a            # one batch
 #   python3 assets/_regen.py --list                # what batches exist
 #   python3 assets/_regen.py --all                 # everything not already done