feat(foundry): revert actions to queue/workflow pattern with direct sends

Revert actor communication from direct action calls to queue/workflow-based
patterns for better observability (workflow history in RivetKit inspector),
replay/recovery semantics, and idiomatic RivetKit usage.

- Add queue/workflow infrastructure to all actors: organization, task, user,
  github-data, sandbox, and audit-log
- Mutations route through named queues processed by workflow command loops
  with ctx.step() wrapping for c.state/c.db access and observability
- Remove command action wrappers (~460 lines) — callers use .send() directly
  to queue names with expectQueueResponse() for wait:true results
- Keep sendPrompt and runProcess as direct sandbox actions (long-running /
  large responses that would block the workflow loop or exceed 128KB limit)
- Fix workspace fire-and-forget calls (enqueueWorkspaceEnsureSession,
  enqueueWorkspaceRefresh) to self-send to task queue instead of calling
  directly outside workflow step context

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

foundry/packages/backend/src/actors/handles.ts

@@ -79,3 +79,7 @@ export function selfUser(c: any) {
 export function selfGithubData(c: any) {
   return actorClient(c).githubData.getForId(c.actorId);
 }
+
+export function selfTaskSandbox(c: any) {
+  return actorClient(c).taskSandbox.getForId(c.actorId);
+}