maude: owise (otherwise) equations (8 tests, 229 total)

Parser reads trailing eq attributes (eq L = R [owise] .) via mau/split-attrs.
mau/crewrite-top is two-pass: ordinary equations first, owise last — an owise
catch-all fires only when no ordinary equation applies, regardless of
declaration order. Verified a catch-all declared first still defers.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

plans/maude-on-sx.md

@@ -112,6 +112,11 @@ The novel substrate stress: equational matching. Pattern `X + Y` against `1 + 2
 - [x] Witness-path search (`lib/maude/searchpath.sx`) — `mau/search-path` /
   `mau/search-length` return the shortest sequence of states start..goal (the
   solution moves), not just yes/no. 8 tests.
+- [x] `owise` equations — parser now reads trailing eq attributes
+  (`eq L = R [owise] .`), `mau/split-attrs`; `mau/crewrite-top` is two-pass
+  (ordinary equations first, owise last), so an owise catch-all fires only when
+  nothing else applies, regardless of declaration order. Parser also reads
+  `label`/`prec`/`owise`/`id:` eq+op attrs. 8 tests.
 
 ### Phase 8 — Propose `lib/guest/rewriting/`
 - [ ] Extract equational matching engine (the most reusable piece).