Add Teams message history API

[heyitsaamir]

Summary

Adds a Microsoft Graph-backed Teams message history API for context-level and app-level callers, plus a focused example app for manual testing. History now returns both the messages and a serializable source that can be reused for future reads.

API

Reactive context API

history = await ctx.get_history(10)
messages = history.messages
source = history.source

ctx.get_history(n) infers the current scope from the inbound activity and returns MessageHistory(messages, source):

• 1:1 chat / group chat: calls Graph GET /chats/{chat-id}/messages
• Team channel: calls Graph GET /teams/{team-aad-group-id}/channels/{channel-id}/messages
• Channel thread: detects reply_to_id or ;messageid=<root> and calls .../messages/{root-message-id}/replies

For channel history, the SDK requires the Teams activity to include team.aad_group_id; this is the Graph team resource ID used by RSC.

App-level API

history = await app.get_history(n=10, source=source)

app.get_history intentionally takes a HistorySource instead of individual IDs. Callers can pass history.source from a previous ctx.get_history(...) result or construct one of the exported source models directly:

source = ChannelHistorySource(
    team_aad_group_id=team_aad_group_id,
    channel_id=channel_id,
    thread_id=message_id,
)
history = await app.get_history(n=10, source=source)

Available source models:

• OneOnOneHistorySource(chat_id=...)
• GroupChatHistorySource(chat_id=...)
• ChannelHistorySource(team_aad_group_id=..., channel_id=..., thread_id=None)

HistorySource is a Pydantic discriminated union, so sources can be persisted with source.model_dump(by_alias=True) and restored with TypeAdapter(HistorySource).validate_python(payload).

The helper returns the latest n messages for the selected source:

• Chat/group chat requests use Graph $orderby=createdDateTime desc with $top.
• Channel root messages use Graph's channel ordering, which is by last modified date of the entire reply chain.
• Channel thread replies only support $top; the SDK pages through replies and returns the last n by created_date_time when timestamps are available.

Graph errors propagate unchanged.

Caveats

• 1:1 chat history depends on service-side support that is expected to be picked up very soon by the service team.

Example

Adds examples/history with commands to test:

• history / history ctx <n>
• history chat <chat-id> [n]
• history channel <team-aad-group-id> <channel-id> [n]
• history thread <team-aad-group-id> <channel-id> <thread-id> [n]