docs(release): correct phantom-feature framing before PyPI cut

CHANGELOG:
- Drop false gchat file-delivery bullet (PR #112 never merged; upstream
  itself does not implement gchat outbound file delivery)
- Fix Slack DM block-action citation to merged PR #137 (supersedes #133)
- Re-point 0.4.27.1 vehicle from unmerged #120 to tag v0.4.27.1 + #117
- Drop numberless Twilio 'scaffolding PR' (only #142 exists)

UPSTREAM_SYNC:
- Reframe Google Chat outbound file delivery as parity (upstream also
  logs 'not yet supported' + media.upload TODO, index.ts:1282-1289)
- Correct Teams cert-auth row: TS is not 'Supported' — config throws at
  startup in both SDKs (types.ts:31, config.ts:13); parity, issue #58
- Add Messenger get_user row: upstream has no getUser; raising stub is
  parity, Graph-API impl tracked as #132

Author: patrick-chinchill

CHANGELOG.md

@@ -6,7 +6,7 @@ Synced to upstream `vercel/chat@4.30.0`. The mapped core (`packages/chat/src`) i
 
 ### New adapter: Twilio (SMS / MMS / Voice)
 
-- **`chat_sdk.adapters.twilio`** (vercel/chat#558; PRs #142 + the scaffolding PR). Twilio Programmable Messaging adapter (10th platform): inbound message webhooks with `X-Twilio-Signature` HMAC-SHA1 verification (`hmac.compare_digest`), outbound SMS/MMS through the Messages REST API (hand-rolled over an injectable transport — no official `twilio` SDK, mirroring upstream), 1:1 DM threads keyed `twilio:{sender}:{recipient}`, plus standalone `api` / `webhook` / `voice` helpers (TwiML builders, call + transcription parsing). New extra: `chat-sdk-python[twilio]`. Imports stay lazy so the package loads without `aiohttp` installed.
+- **`chat_sdk.adapters.twilio`** (vercel/chat#558; PR #142). Twilio Programmable Messaging adapter (10th platform): inbound message webhooks with `X-Twilio-Signature` HMAC-SHA1 verification (`hmac.compare_digest`), outbound SMS/MMS through the Messages REST API (hand-rolled over an injectable transport — no official `twilio` SDK, mirroring upstream), 1:1 DM threads keyed `twilio:{sender}:{recipient}`, plus standalone `api` / `webhook` / `voice` helpers (TwiML builders, call + transcription parsing). New extra: `chat-sdk-python[twilio]`. Imports stay lazy so the package loads without `aiohttp` installed.
 
 ### Teams adapter: migration to the official `microsoft-teams-apps` SDK (issue #93)
 
@@ -80,8 +80,7 @@ Synced to upstream `vercel/chat@4.29.0` (release commit `6581d31`, May 18 2026;
 ### Python-only improvements
 
 - **Slack `files_upload_v2` confirmation surfaced through `post()`** (PR #117; also shipped early as 0.4.27.1). `SentMessage.raw` carries `uploaded_file_ids`; history persistence nulls `raw` to avoid storage bloat/PII.
-- **Slack: DM block-action responses no longer thread** (PR #133). `_handle_block_actions` mirrors `_handle_message_event`'s DM handling so HITL button replies don't create phantom "1 reply" threads.
-- **Google Chat: file delivery via multipart media upload** (PR #112).
+- **Slack: DM block-action responses no longer thread** (PR #137, supersedes #133). `_handle_block_actions` mirrors `_handle_message_event`'s DM handling so HITL button replies don't create phantom "1 reply" threads.
 
 ### Not ported / deferred (documented in docs/UPSTREAM_SYNC.md)
 
@@ -98,7 +97,7 @@ Synced to upstream `vercel/chat@4.29.0` (release commit `6581d31`, May 18 2026;
 
 ## 0.4.27.1 (2026-05-29)
 
-Python-only point release on the 0.4.27 line (branched from `v0.4.27`; PR #120). Backports the Slack `files_upload_v2` confirmation fix (PR #117) so `SentMessage.raw` carries `uploaded_file_ids`, plus the history-persistence `raw` null-out. Shipped ahead of 0.4.29 to unblock chinchill-api's delivery-confirmation gating.
+Python-only point release on the 0.4.27 line (branched from `v0.4.27`; shipped via tag `v0.4.27.1` + merged PR #117). Backports the Slack `files_upload_v2` confirmation fix (PR #117) so `SentMessage.raw` carries `uploaded_file_ids`, plus the history-persistence `raw` null-out. Shipped ahead of 0.4.29 to unblock chinchill-api's delivery-confirmation gating.
 
 ## 0.4.29a2 (2026-05-28)
 

docs/UPSTREAM_SYNC.md

@@ -655,15 +655,16 @@ stay explicit instead of being rediscovered in code review.
 
 | Area | Python | TS | Rationale |
 |------|--------|-----|-----------|
-| Teams certificate auth | Rejected (app password only) | Supported | Low demand; can add later |
+| Teams certificate auth | Config accepted, **throws at startup** (not yet supported) | **Same** — config shape present but throws at startup, not yet supported (`adapter-teams/src/types.ts:31`, `config.ts:13`) | **Parity — neither SDK implements Teams certificate auth yet**; both carry the deprecated `certificate` config that throws at startup. Tracked as issue #58. |
 | Teams `dialog_open_timeout_ms` config | Not implemented | Configurable | Low demand |
-| Google Chat outbound file delivery | Files attached to an outbound message are dropped — `post_message` logs "File uploads are not yet supported for Google Chat" and posts text/cards only (no media upload). Inbound attachments **are** parsed: `_create_attachment` builds a full `Attachment` (type detection, `fetch_data` download closure, `fetch_metadata`) for every `message.attachment` entry. | Both directions supported (multipart media upload on send) | Outbound upload (multipart to the Media API) not yet ported; API complexity, can add later. Inbound parity is complete, so this row is outbound-only. |
+| Google Chat outbound file delivery | Inbound attachment parsing implemented — `_create_attachment` builds a full `Attachment` (type detection, `fetch_data` download closure, `fetch_metadata`) for every `message.attachment` entry. Outbound file delivery logs "File uploads are not yet supported for Google Chat" and ignores files (posts text/cards only, no media upload). | **Same** — logs "File uploads are not yet supported for Google Chat" and leaves a `media.upload` TODO (`adapter-gchat/src/index.ts:1282-1289`). | **Parity — neither SDK implements Google Chat outbound file delivery.** A Python-only enhancement attempt (PR #112) exists but is unmerged; landing it would be a divergence (upstream lacks it), gated on real need. |
 | Discord Gateway WebSocket | HTTP interactions only | Both HTTP and Gateway | Gateway requires persistent connection |
 | Discord gateway-only interactions (vercel/chat#490) | Handled on the forwarded-event surface: a `GATEWAY_INTERACTION_CREATE` envelope (raw INTERACTION_CREATE dispatch payload in `data`) is deferred via `POST /interactions/{id}/{token}/callback` (type 5 slash / type 6 component) and routed through the existing HTTP interaction handlers; a malformed forward missing `id`/`token` is logged and skipped | Upstream handles `Events.InteractionCreate` directly on the resident discord.js client via `deferReply()`/`deferUpdate()`; the upstream forwarder never forwards interactions | Python has no resident Gateway client (row above), so gateway-only deployments run an external listener shim that forwards raw dispatch payloads (`x-discord-gateway-token`). Observable wire behavior is identical — same callback REST calls, same handler routing, same `@original` deferred-response resolution. |
 | Teams `User-Agent: Vercel.ChatSDK` outbound header | Not set on `aiohttp` calls | Propagated by `botbuilder` 2.0.8 | Python Teams adapter doesn't use `botbuilder` (raw `aiohttp`). Upstream's vercel/chat#415 was a JS-only `botbuilder` SDK bump that flipped `X-User-Agent` → `User-Agent`. No equivalent dependency to bump on the Python side. Setting a `User-Agent` on the ~9 outbound `aiohttp` call sites would be a defense-in-depth nice-to-have; deferred to a follow-up. |
 | Teams adapter on `microsoft-teams-apps` (official MS Python SDK) | Inbound webhook + JWT auth, outbound send/edit/delete/typing, and native DM streaming all delegate to the official `microsoft-teams-apps` SDK `App`; Graph reads stay hand-rolled over `aiohttp` | `@microsoft/teams.apps` owns the wire format, throttling, and activity routing | **Delivered in 0.4.30** (issue #93, PRs 1–4). The migration shipped as four PRs: inbound + auth (#143), outbound (#144), native streaming via the SDK `IStreamer` (#145), and this release cut. The 3.12 floor bump (#111) — the migration's prerequisite — landed in 0.4.29. The residual adapter-level divergences (we keep the SDK as auth + transport but route the authenticated activity ourselves; close the streamer in our own `finally` because our bridge owns dispatch) are documented in the Teams divergence rows above. Graph stays hand-rolled (no `msgraph-sdk` / `[graph]` extra). |
 | Telegram `get_user().is_bot` | Always `False` (matches upstream — `getChat` does not expose `is_bot`) | Always `false` (same caveat documented in upstream code comment) | The Telegram Bot API's `getChat` endpoint does not surface the `is_bot` field that's available on the `User` object inside incoming `Message` updates. Callers needing bot detection must use `message.author.is_bot` from webhooks instead of `chat.get_user(...).is_bot`. |
 | WhatsApp `get_user` | Raises `ChatNotImplementedError` (`Chat.get_user` translates to "does not support get_user") | Not implemented upstream either (no `getUser` on the WhatsApp adapter) | WhatsApp Cloud API has no user lookup endpoint — phone numbers are the only stable identifier and there's no equivalent of `users.info` exposed to business apps. Documented explicitly so callers don't expect parity with Slack/Teams/Discord. |
+| Messenger `get_user` | Raising stub (`ChatNotImplementedError`); a Graph-API-backed impl is tracked as issue #132 | No `getUser` method on the Messenger adapter | **Parity — upstream Messenger has no user-lookup method**; the Python raising stub matches. (Meta's Graph API *could* back a real implementation, unlike WhatsApp — hence #132 stays open as an enhancement.) |
 | Linear agent sessions | Not ported — the ~120-reference agent-sessions surface (`parseMessageFromAgentSessionEvent`, `agentActivity`, `AgentSessionEventWebhookPayload`, `LinearAgentSessionThreadId`, …) is absent from the Python `LinearAdapter` | Full agent-sessions support (`adapter-linear` 4.27.0, `bc94f0a`): parses agent-session webhook events into messages, emits agent activity, and routes the agent-session thread id | Largest single gap from the 0.4.30 audit; pre-existing (present since 0.4.29). Deferred to the 4.31 wave — tracked in **#151**. |
 | `adapter-web` (`@chat-adapter/web`) | Neither half ported. (a) The server-side `WebAdapter` is **deferred** — not yet ported; (b) the client subpaths are out of scope (see Rationale). | Two distinct things: (a) a server-side `WebAdapter` — an `Adapter` implementation serving a browser chat UI over the AI SDK UI stream protocol (`3490a8c`, vercel/chat#444); (b) React/Vue/Svelte client subpaths (`716e934`) | The `WebAdapter` (a) **is portable** to a Python server SDK (it's a standard `Adapter`) and is deferred, not excluded — a future wave can port it. The client subpaths (b) are genuinely browser-only (front-end framework bindings) and are out of scope for a Python server SDK. (Corrects the earlier over-broad "browser-only; no Python runtime" note in CHANGELOG.) |