maude: Phase 7 reflection / META-LEVEL (18 tests, 196 total)

lib/maude/meta.sx — up-term/down-term encode terms as data (mt-var/mt-app),
reflective meta-reduce/meta-rewrite/meta-apply, the meta-circular law
down(metaReduce(up t)) =AC= reduce t, and meta-prove-equal? as a generic
equational theorem helper. Verified round-trips, reflection agreement,
single-rule meta-apply, and proving commutativity/associativity instances.

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

lib/maude/conformance.conf

@@ -14,6 +14,7 @@ PRELOADS=(
   lib/maude/fire.sx
   lib/maude/rewrite.sx
   lib/maude/strategy.sx
+  lib/maude/meta.sx
 )
 
 SUITES=(
@@ -23,4 +24,5 @@ SUITES=(
   "conditional:lib/maude/tests/conditional.sx:(mau-conditional-tests-run!)"
   "rewrite:lib/maude/tests/rewrite.sx:(mau-rewrite-tests-run!)"
   "strategy:lib/maude/tests/strategy.sx:(mau-strategy-tests-run!)"
+  "meta:lib/maude/tests/meta.sx:(mau-meta-tests-run!)"
 )