sync(bfmono): fix(gambit): preserve shared references in safe session serialization (+19 more) (bfmono@13c4c8c22)

This PR is an automated gambitmono sync of bfmono Gambit packages.

- Source: `packages/gambit/`
- Core: `packages/gambit/packages/gambit-core/`
- bfmono rev: 13c4c8c22

Changes:
- 13c4c8c22 fix(gambit): preserve shared references in safe session serialization
- ae392aa24 feat(gambit-simulator-ui): add grader error chips to workbench chat
- 1de6b335c fix(gambit): clamp deck-level maxTurns bounds in test run selection
- 01d7abbb9 fix(gambit): default verify tab bootstrap flag to enabled
- f3d186c7b fix(gambit): include extension schemas in exports and default serve to restored workspace
- a83b7cbe7 fix(gambit): move unbounded build timeout to deck opt-in
- acb2de627 fix(gambit): avoid strict json_schema 400s in openrouter responses
- 8aba573b6 fix(gambit-simulator-ui): treat errored calibrate runs as failed
- ca2028cf8 fix(gambit): prevent circular trace crashes in workspace test run API
- 7e41517e5 fix(gambit): make build assistant run timeout unbounded
- 24341143d feat(gambit): add deterministic verify fixture seeding
- ff2c2d33d feat(gambit): add verify tab consistency UI
- 91f0c93bb feat(gambit): add feature-flagged verify routing
- 1392f8b65 feat(gambit): support deck-level maxTurns override
- f5920ef86 chore(gambit): cut 0.8.5-rc.10
- 073c84d0e chore(gambit): cut 0.8.5-rc.10
- 2c669ba51 fix(gambit-core): ship builtin snippets/decks in npm runtime layouts
- 498708844 docs(gambit): retire synthetic respond/end guidance and align deck authoring surfaces
- 35ad1d5b5 feat(gambit-core): add OpenResponses convergence runtime, extensions, and async action semantics
- b2d78cfb3 chore(gambit): cut 0.8.5-rc.9

Do not edit this repo directly; make changes in bfmono and re-run the sync.

Author: bft-codebot

src/server_session_store.ts

@@ -196,17 +196,20 @@ const normalizeEventType = (
 };
 
 const safeStringify = (value: unknown, space?: number): string => {
-  const seen = new WeakSet<object>();
+  const stack: Array<unknown> = [];
   return JSON.stringify(
     value,
-    (_key, candidate) => {
+    function (_key, candidate) {
       if (!candidate || typeof candidate !== "object") {
         return candidate;
       }
-      if (seen.has(candidate as object)) {
+      while (stack.length > 0 && stack[stack.length - 1] !== this) {
+        stack.pop();
+      }
+      if (stack.includes(candidate)) {
         return "[Circular]";
       }
-      seen.add(candidate as object);
+      stack.push(candidate);
       return candidate;
     },
     space,