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.

docs/core-data-structures/session.md

@@ -196,6 +196,20 @@ export interface SurfaceNode {
 }
 ```
 
+## `SessionRegistrationReservation` — unpublished identity and construction ownership
+
+A session factory reserves its public `SessionId` before awaiting persistence load or scoped setup, so concurrent code cannot create, prepare, or enter a session under that id ahead of the transaction. The opaque capability may construct exactly one unpublished `Session` and authorizes exactly that object at `enter()`. Its `release` function is the exact Cordis owner effect disposer, letting the lifecycle adopt it by identity and place release after scope quiescence while owner disposal remains the abandoned-transaction backstop. Ordinary session consumers use `create()` and never hold this type.
+
+Source: [`packages/core/session/src/index.ts`](../../packages/core/session/src/index.ts)
+
+```ts type-equiv
+interface SessionRegistrationReservation {
+  readonly id: SessionId
+  prepare(options?: CreateSessionOptions): Session
+  release(): void
+}
+```
+
 ## Derived history: `deriveMessages()` and `deriveEventMessage()`
 
 `Session.deriveMessages()` projects the event log into the `Message[]` the model sees — cached (each surface node projected once, when first seen; a surface rewrite rebuilds) and frozen (a fresh array per call over shared, deep-frozen messages, so mutating logged history through a projection is unrepresentable). `deriveEventMessage(event)` is the per-node pure function the fold applies — public so external reconstructors and the dev invariant project a log prefix with exactly the same rules and cannot disagree with the cache. The projection rules: