refactor: replace maxRounds with supervisor check interval

Removes maxRounds as a hard stop limit from the entire stack. The supervisor
(already configured via workflow.yaml supervisorInterval) is now the sole
termination authority.

Changes across 27 files in 11 packages:
- workflow-protocol: StartStep.meta is now empty, StartNodePayload drops maxRounds
- workflow-cas: isStartPayload no longer checks maxRounds
- workflow-execute: engine, worker, fork-thread all stripped of maxRounds plumbing
- cli-workflow: --max-rounds flag removed from CLI and HTTP API
- workflow-runtime: build-context and create-workflow no longer reference maxRounds
- workflow-dashboard: UI no longer sends maxRounds
- workflow-template-develop/solve-issue: moderator no longer checks rounds remaining
- All tests updated

Fixes #185

packages/workflow-protocol/__tests__/moderator-table.test.ts

@@ -24,7 +24,7 @@ function makeCtx(roles: (keyof TestMeta & string)[]): ModeratorContext<TestMeta>
     start: {
       role: START,
       content: "test",
-      meta: { maxRounds: 10 },
+      meta: {},
       timestamp: Date.now(),
     } as StartStep,
     steps,

packages/workflow-protocol/src/cas-types.ts

@@ -3,7 +3,6 @@
 export type StartNodePayload = {
   name: string;
   hash: string;
-  maxRounds: number;
   depth: number;
 };
 

packages/workflow-protocol/src/types.ts

@@ -46,7 +46,7 @@ export type RoleOutput = {
 export type StartStep = {
   role: typeof START;
   content: string;
-  meta: { maxRounds: number };
+  meta: Record<string, never>;
   timestamp: number;
 };