feat(mcpl): journal channel and push event coalescing

README.md

@@ -239,6 +239,49 @@ Optional host-side implementation of the MCP Live protocol. External servers (ga
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+[RFC-006](https://github.com/anima-research/mcpl/pull/5) coalescing works across
+`push/event` and `channels/incoming`. The host advertises `pushEvents`, `deferred`,
+`channelsIncoming`, and `channelScopedPush` under `eventCoalescing`.
+
+An optional `coalesce: { key }` keeps the newest unread occurrence. Channel messages
+require an occurrence `eventId` while retaining their stable platform `messageId`.
+A push with `coalesce.channelId` shares that registered channel's subject namespace, so a
+create arriving through one method can be edited or deleted through the other. Scope is
+never inferred from `origin`. Both lanes check `channels.incoming`, current registration,
+and the server config's optional `allowedIncomingChannels` allow-list (`*` globs; an empty
+list denies all). A channel-scoped push also needs ordinary push authorization.
+
+Add `deferred: true` to a push to render a batch through `push/render` at activation
+assembly; deferred mode is not valid on `channels/incoming`. Use `retract: true` to remove
+unread work. Channel retractions require a deletion notice, which is appended when earlier
+versions were consumed or their history is uncertain. Reply targets, conversation-fork
+routing, and channel provenance survive mixed-lane updates.
+
+Pending events stay outside context managers until activation assembly. Shared-context
+publication waits for the other residents' live turns to finish; isolated conversation
+forks receive their own events. Consumed history is never rewritten. Pending work,
+subject history, and occurrence receipts are reconstructed from the journal; recovery waits for
+a fresh grant and channel registration, and does not repeat old source-backed renders.
+Changing a configured endpoint/command creates a separate server-binding namespace. Use a
+different server ID if credentials switch to another principal at the same endpoint.
+
+`mcpl/coalescing-journal` is the authoritative append-only operation log. Acceptance,
+replacement, retraction, render decisions, and delivery receipts are durable appends.
+A pure reducer rebuilds pending work and the occurrence index; replay itself performs no
+RPCs, context writes, or wakes. Assembly appends a publication intent before writing
+context, then appends completion. The intent seals that occurrence against replacement;
+a journal-owned delivery ID makes an interrupted publication safe to retry.
+
+Older experimental pending/receipt stores are imported once into the journal. Their
+uncertain pending deliveries are sealed conservatively and checked against legacy context
+markers before publication; subsequent recovery never consults those old stores. Startup
+currently replays the full journal and keeps receipt positions in memory, so recovery cost
+and index memory grow with journal history. Rendering times out after five seconds. The
+host retains 64 notices per batch, caps notice data at 4 KiB and content at 1 MiB, and
+tracks up to 128 active subjects.
+Excess pending subjects are rejected rather than silently dropped. Coalesced debounce
+uses its own fixed deadline and does not change unrelated events' quiet periods.
+
 ### Streaming Lifecycle
 
 1. **Start**: Framework calls `agent.startStreamWithInjections()` → `YieldingStream`

changelog.d/mcpl-channel-registration.breaking.md

@@ -0,0 +1 @@
+- **MCPL server authors:** incoming channel content now requires an authoritative registration, including when coalescing is absent. Servers that relied on an outbound placeholder inferred from push `origin` must send `channels/register`/`channels/changed` or complete a host-authorized `channels/open` with a valid descriptor first. Outbound reply routing and conforming registered-channel delivery are unchanged.

changelog.d/mcpl-event-coalescing.added.md

@@ -0,0 +1,4 @@
+- Support RFC-006 coalescing across `push/event` and `channels/incoming`, including stable message identity, channel-scoped edits/deletions, deferred rendering, conversation routing, durable recovery/receipts, and current-grant checks. Channel retractions preserve consumed history and require a deletion notice.
+- Add optional MCPL server `allowedIncomingChannels` patterns, enforced on both incoming messages and channel-scoped pushes. Host-derived outbound routing placeholders do not authorize inbound channel content.
+- Keep coalesced wake deadlines separate from ordinary debounce and cancel obsolete queued wakes. Shared-context materialization waits for safe turn boundaries across residents.
+- Make an append-only Chronicle operation journal authoritative for coalescing. Rebuild pending work and occurrence receipts through pure replay; use durable publication intents and stable context delivery IDs to recover interrupted publication without duplicate messages. Import older experimental state once.