go: panic + recover → eval 92/92, total 509/509, Phase 6 closed [shapes-scheduler]

Panic/recover builtins + per-frame __go-panic-cell of shape
(STATE V). Body panic flips cell :none→:raised BEFORE defers drain
so recover() can find it. recover() walks env chain past shadowing
cells to the outermost :raised one — flips it :recovered, returns V.
Frame exit checks cell: :recovered → return clean; :raised →
propagate (:go-panic V).

6 tests: uncaught-from-program, panic-from-fn, defer-recover-swallow,
recover-captures-via-channel, propagation-through-no-defer-chain,
middle-frame-catches-deeper-panic.

Shape: panic cell is a frame-attached out-of-band channel that
survives function boundaries via env-chain walk. Same primitive
slots into the scheduler kit's termination-record + cleanup-with-
error-context hook. Maps cleanly to Erlang try/catch/after.

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

lib/go/scoreboard.json

@@ -1,12 +1,12 @@
 {
   "language": "go",
-  "total_pass": 503,
-  "total": 503,
+  "total_pass": 509,
+  "total": 509,
   "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":86,"total":86,"status":"ok"},
+    {"name":"eval","pass":92,"total":92,"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"}