go: defer + LIFO drain → eval 86/86, total 503/503 [shapes-scheduler]

Phase 6 first slice. New :defer stmt dispatch, go-eval-defer-stmt
captures (callee, eagerly-evaluated args) onto a frame-local
__go-defer-stack mutable list. go-eval-call installs the stack and
drains LIFO before returning; go-eval-program does the same for
the implicit main frame. New :quoted-value AST node lets defer
re-invoke calls with the frozen arg values.

6 eval tests: single defer, multi-LIFO, args-eager-at-defer-time,
fires-on-early-return, frame-local (no bleed to outer), defer-in-loop.

Shape: defer is a per-frame cleanup queue (LIFO on frame exit) that
the scheduler kit will reuse for panic-unwind + clean-exit + select-
case-rollback paths. Distinct from the scheduler's ready-queue —
diary updated to keep that distinction explicit.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lib/go/scoreboard.json

@@ -1,12 +1,12 @@
 {
   "language": "go",
-  "total_pass": 497,
-  "total": 497,
+  "total_pass": 503,
+  "total": 503,
   "suites": [
     {"name":"lex","pass":129,"total":129,"status":"ok"},
     {"name":"parse","pass":176,"total":176,"status":"ok"},
     {"name":"types","pass":72,"total":72,"status":"ok"},
-    {"name":"eval","pass":80,"total":80,"status":"ok"},
+    {"name":"eval","pass":86,"total":86,"status":"ok"},
     {"name":"runtime","pass":40,"total":40,"status":"ok"},
     {"name":"stdlib","pass":0,"total":0,"status":"pending"},
     {"name":"e2e","pass":0,"total":0,"status":"pending"}