docs(agent): pico3: forbid AsyncLocalStorage; nested-line detection via Chord context key

packages/agent/docs/pico/v3/hardening-handoff.md

@@ -238,7 +238,7 @@ Retain and expand the existing recovery tests for generation, tool, collapse, jo
 ### 7. Session line, failure, and cancellation
 
 - Every storage interaction, waiter registration, watch capture, registry mutation, reservation, and commit enters one FIFO Session line.
-- Known nested Session-line entry rejects immediately.
+- **No `AsyncLocalStorage` / `node:async_hooks`, anywhere.** Nested-line detection uses Chord contexts only: the Session derives a line context for every callback it runs (`withContextValue(LINE_KEY, marker, ctx)` with a private `createContextKey`), passes it to transaction builders (`commit((tx, ctx) => …)`; task builders receive `(tx, current, ctx)`), and `commit`/`read`/`onLine` reject `NestedLineOperation` when the supplied `ctx` carries `LINE_KEY`. Inside a builder, authors use the builder's `ctx` for everything; calling the Session from inside a builder with an outer ctx is a documented, undetectable self-wait, not something the kernel prevents.
 - Check caller cancellation before queuing and again before invoking a transaction callback.
 - Once persistence starts, call `Storage.commit` exactly once with `withoutAbortSignal(ctx)`.
 - A storage commit rejection faults the Session, closes storage with a non-cancellable context, and makes already-queued/later operations reject `Faulted`.

packages/agent/docs/pico/v3/plugins.md

@@ -220,7 +220,8 @@ that task, no cleanup code); state that outlives tasks goes in a **namespace**.
 There is no hook invocation id: nothing durable identifies "the same handler
 invocation" across a crash or a reload, and the rerun must find the earlier
 decision. Hooks commit through `h.conversation(api.conversationId, ctx)`
-handles and may wait as long as they like; `beforeTool` handlers rerun after a
+handles (never from inside a transaction builder: use the builder's own `ctx`
+there, see `hardening-handoff.md` §7) and may wait as long as they like; `beforeTool` handlers rerun after a
 crash or a suspend/reopen (they run before `started`), which is why their
 decision must be a memo.
 

packages/agent/docs/pico/v3/view-and-events.md

@@ -496,6 +496,8 @@ rules are:
   `model`, so context derivation needs no special case.
 - Envelope assembly happens on the line; listener dispatch off the line,
   synchronous and in order; a listener throw closes that watch only.
+- No `AsyncLocalStorage`: line re-entry is detected through the Chord context
+  the Session hands to its callbacks (`hardening-handoff.md` §7).
 - Chord bridge (`plugins.md` §6.1): a bounded ordered adapter applies one raw
   envelope's ops to the Chord `MutableReplicatedState` and calls `publish()` in
   the same synchronous block (Chord's `subscribe()` publishes pending mutations