An options map for the resolvers, and sid beside the clip it is in

Finishing the last commit, which traded a simpler definition for noisier call
sites: deleting the arity ladders left `(symbol/resolver sym st pal/index-of
nil nil)` at twenty-odd places, and two trailing nils tell a reader nothing
except to go and count positions.

The ladder was a symptom. The disease is five positional parameters, and the
split that matters is which of them are OPTIONAL:

  store, palette    positional, because neither is optional. A dense channel
                    cannot be read without the store it names — that is the
                    crash two commits ago — and every op carries a colour.
  pose-tracks       one call site, in `clip/resolver`'s own recursion
  source/picture-fps  two call sites

So the last three become one `opts` map, and the common call loses a nil. The
point is not the nil: it is that the sixth option, whenever it arrives, is a
key at one call site rather than a nil at fifty.

`clip/resolver` also had `sid` FOURTH, behind two arguments that say nothing
about which symbol is being resolved. It is second now, beside the clip it is
in: `(clip/resolver c :main store pal/index-of nil)`.

62 call sites rewritten by parsing the forms rather than by regex, because
`clip/resolver`'s arguments move past each other and a regex cannot see that.
An earlier attempt at this dropped `palette` on the floor and still compiled
at 62 sites — it only surfaced as an arity error, so if that had been a
same-arity mistake the tests would have been the last line of defence.

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

frontend/test/arthur/domain/gesture_test.cljs

@@ -34,7 +34,7 @@
 
 (defn- drawn [c path]
   (partition 2 (take 6 (array-seq (:pts (first (filter #(= path (:node %))
-                                                         ((clip/resolver c nil pal/index-of :main nil) 16))))))))
+                                                         ((clip/resolver c :main nil pal/index-of nil) 16))))))))
 
 (defn- near? [a b] (every? #(< (js/Math.abs %) 1e-9) (map - (flatten a) (flatten b))))