apl: :Trap exception machinery — Phase 7 complete (+5 tests, 450/450)

apl-throw raises a tagged ("apl-error" code msg) error.
apl-trap-matches? checks if codes list contains the error's code
(0 = catch-all, à la Dyalog).

Eval-stmt :trap clause wraps try-block with R7RS guard;
on match, runs catch-block; on mismatch, re-raises.
Bonus :throw AST node for testing.

test.sh + conformance.sh now load lib/r7rs.sx (for guard) and
include eval-ops + pipeline suites in scoreboard.

All Phase 7 unchecked items are now ticked.
Final scoreboard: 450/450 across 10 suites.

lib/apl/runtime.sx

@@ -971,6 +971,20 @@
 
 (define apl-quad-print (fn (arr) arr))
 
+(define apl-throw (fn (code msg) (raise (list "apl-error" code msg))))
+
+(define
+  apl-trap-matches?
+  (fn
+    (codes e)
+    (and
+      (list? e)
+      (>= (len e) 2)
+      (= (first e) "apl-error")
+      (or
+        (some (fn (c) (= c 0)) codes)
+        (some (fn (c) (= c (nth e 1))) codes)))))
+
 (define
   apl-reduce
   (fn