workflow, subagent: fix Codex code-review round-1 blockers

Six verified A-findings from the code-stage review, each with a regression test:

- parallel()/pipeline() resolved to HOST arrays inside the vm realm, exposing
  host Array.prototype to scripts; combinator results are now realm-built
  (in-realm Array.from bound at context setup).
- materializeFromRealm ran proxy traps (ownKeys/getOwnPropertyDescriptor/
  getPrototypeOf) during the descriptor walk — realm code on the host stack,
  outside the vm timeout, escaping as raw errors; proxies (root, nested, and
  in the prototype position) are now rejected trap-free via util.types.isProxy
  before any inspection.
- an already-aborted signal or an immediate cancel() no longer reports
  'completed' for a hook-free script: drive() checks cancellation before
  running the body and again when the script settles.
- dispose() now waits (bounded by disposeGraceMs) for stray agent() children
  to FINISH disposing, not just for the script to settle: every agent() call
  is tracked and quiesce() drains the in-flight set.
- workflow/* event payloads were live mutable aliases shared across emissions;
  emitWorkflowEvent now hands each listener its own structural clone.
- the structured-output turn-continuation veto is now prepend: true, so an
  earlier-registered force-continue listener cannot short-circuit it.

Docs updated in the same change (READMEs, core-data-structures/workflow.md,
the dynamic-workflows RFC, regenerated cordis catalogs).

packages/workflow/workflow-vm/tests/meta.spec.ts

@@ -108,6 +108,14 @@ return 2`
     expect(error.message).toContain('JSON data')
   })
 
+  it('rejects a meta literal containing a proxy as META_INVALID — its traps never run', () => {
+    // bad() rethrows anything that is not a WorkflowError, so a trap firing
+    // ('trap ran') would fail this test instead of mapping to META_INVALID.
+    const error = bad('export const meta = { name: "x", description: "d", phases: new Proxy([], { getPrototypeOf() { throw new Error("trap ran") } }) }')
+    expect(error.code).toBe('META_INVALID')
+    expect(error.message).toContain('proxies cannot cross')
+  })
+
   it('rejects shape violations with EVERY violation listed (META_INVALID)', () => {
     const error = bad('export const meta = { description: 7, bogus: 1 }\nreturn 1')
     expect(error.code).toBe('META_INVALID')