fix(scope): harden lifecycle ownership foundation

Make Cordis construction and teardown ownership reentrancy-safe, then carry caller and provider ownership through reservation, setup, publication, quiescence, and sentinel retirement.

Stabilize registry carriers and factory/workflow boundaries, add adversarial lifecycle regressions, and align the rewritten RFC plus generated contracts with the enforced behavior.

packages/core/agent-loop/README.md

@@ -8,7 +8,9 @@ This is the only package in the harness that contains concrete loop logic. Every
 
 ### Public API
 
-Lifecycle (scoped): programmatic creation and resume snapshot caller-owned identity/configuration data, obtain registry/store-owned capabilities for both unpublished IDs, mint `agent.ctx`, and install the ordered teardown skeleton before awaiting optional `setup`. The capabilities reject competing `register`/`enter`/`prepare`/`create` calls, so setup cannot publish the factory objects or same-id replacements. A create hands one-read raw seed and metadata references synchronously to the session boundary, which rejects exotic shells and materializes accepted values in a single recursive pass; pre-cloning either value could incorrectly sanitize prototypes. Resume installs an owner-liveness sentinel before persistence load, captures each loaded metadata field once, then hands ownership directly to the full lifecycle. After setup resolves, the factory checks its lifecycle flag, owner-fiber state, and owning agent status around one microtask checkpoint so a same-turn Cordis unload wins before publication. Successful setup inserts both session and agent before announcing either, enables driving immediately before `agent/session-start`, then starts the loop. The concrete agent owns runtime-pinned `id`, frozen detached `options`, `session`, and `ctx` bindings. Load/setup rejection or owner unload publishes nothing; partial creation announcements are paired during rollback. Teardown runs stop/drain (including outstanding idle-injection flushes) → unregister → detach session → unwind scope. All non-vetoing `agent/*` notifications go through `agentEvents(ctx, agent)`, which contains sync/async listener failures per observer; per-step assembly goes through `assembleContextFor(agent)`; the turn-end durability checkpoint goes through `ctx.sessions.flush(session)`.
+Lifecycle (scoped and dual-owned): programmatic creation and resume snapshot caller-owned identity/configuration data, obtain registry/store-owned capabilities for both unpublished IDs, mint `agent.ctx`, and install the ordered teardown skeleton before awaiting optional `setup`. `AgentFactory.createAgent(ownerCtx, options)` and `resume(ownerCtx, options)` receive caller ownership explicitly; the trace-bound `AgentLoop` receiver still supplies the dependency origin, so a caller that injects only `agents` can create an agent whose scope reaches the loop's `sessions`/`llm`/`tools`/`systemPrompt` surface. The caller owns cancellation and the returned handle, while AgentLoop remains a structural second owner because the live driver depends on that service surface: unloading the provider aborts pending load/setup, tears down live programmatic agents, and awaits the same quiescence and ID-release boundary before its dependencies disappear.
+
+The complete create transaction is factory-tracked before ID reservation/session validation, and both a factory placeholder and lifecycle-long caller sentinel exist before scope minting can reenter plugin lifecycle notifications. The caller sentinel adopts the exact reservation effects and always follows the memoized lifecycle boundary, including handle-first teardown followed by caller unload. Resume adds a load sentinel before persistence I/O; it waits for load settlement until `startOwned` synchronously returns a lifecycle/rollback disposer, then follows that disposer without a handoff gap. The ID capabilities reject competing `register`/`enter`/`prepare`/`create` calls and remain held through scope quiescence. A create hands one-read raw seed and metadata references synchronously to the session boundary, which rejects exotic shells and materializes accepted values in a single recursive pass; pre-cloning either value could incorrectly sanitize prototypes. Resume captures each loaded metadata field once. After setup resolves, the factory checks caller and provider liveness after constructing both registry entries but before the first announcement, after `session/created`, after `agent/created`, and again after `agent/session-start` before starting the driver, so synchronous getter- or listener-triggered teardown wins. A publication-wide barrier flips lifecycle liveness immediately but keeps both entries and `agent.ctx` intact until the current synchronous notification phase unwinds; only then does rollback revoke them. Registry/store entries claim IDs across caller-code commit windows, detach exact objects only, and reuse stable carriers for paired edges. Load/setup rejection or owner unload before announcement emits no creation edge; if teardown begins inside a creation or session-start listener, the already-started notifications are paired during rollback and no live or drivable publication survives. Teardown runs stop/drain (including outstanding idle-injection flushes) → unregister → detach session → unwind scope → release reservations. After quiescence, the caller sentinel and any resume-load sentinel disarm and remove their owner-fiber effects so a long-lived caller does not retain the completed agent and scope. Ordinary non-vetoing `agent/*` notifications go through `agentEvents(ctx, agent)`; the registry's paired disposal edge applies the same failure containment through its captured carrier. Per-step assembly goes through `assembleContextFor(agent)`, and the turn-end durability checkpoint goes through `ctx.sessions.flush(session)`.
 
 - `ctx.agentLoop.create(id: string, options?: AgentOptions, meta?: { cwd?: string }): ReactLoopAgent` — synchronous no-setup create, used directly by programs and by `cordis.yml`-configured agents. It creates a fresh per-run session id `${id}-session-<uuid>` with optional metadata; the uuid avoids colliding with a prior durable log. Each call is a new session (a deliberate demo simplification — a real resume-or-create policy is a TODO). Disposed with the calling fiber.
 
@@ -17,7 +19,7 @@ Lifecycle (scoped): programmatic creation and resume snapshot caller-owned ident
 - `ctx.agents.create({ agentId, sessionId, meta?, seed?, agentOptions?, setup? }): Promise<AgentHandle>` — programmatic create on a caller-supplied `sessionId`, NOT `${id}-session`. It awaits the unpublished setup transaction before returning; `meta` carries cwd/lineage/seed-boundary metadata and `seed` reconstructs a forked child prefix after the session boundary validates and detaches each raw value in one pass. The resolved [`AgentHandle`](../agent/README.md) owns exact teardown.
 - `ctx.agents.resume({ agentId, resumeSessionId, agentOptions?, setup? }): Promise<AgentHandle>` — load a persisted session via `ctx.sessionPersistence` ([session persistence](../../../docs/rfc/implemented/architecture/2026-06-14-session-persistence.md)), reconstruct its history, then await setup against a fresh unpublished agent scope before rollback-covered publication. The live session id is the resumed id; turn numbering and derived history continue from the loaded log. Requires a session-persistence backend (NOT hard-injected — non-persistent demos still work; `resume` rejects with a clear error when persistence is absent). Returns an `AgentHandle`.
 
-The config-driven `ctx.agentLoop.create()` path keeps its agent owned by the loop fiber (it discards the handle) — only the programmatic factory callers (the ACP bridge and in-process subagent backends) hold a handle and own per-agent teardown.
+The config-driven `ctx.agentLoop.create()` path keeps its agent owned by the loop fiber (it discards the handle). For a programmatic agent, the handle holder is the only consumer-facing teardown capability; AgentLoop provider unload is the independent structural teardown edge, not another handle exposed to application code.
 
 ### Injected services