feat(apps): support resetting response streams and streaming error handling

[lilyydu]

Summary

Ports two merged teams.py PRs to TypeScript:

• fix(apps): resolve streaming error handling for 2-minute timeout & content stream not allowed teams.py#453 — streaming error handling for the 2-minute timeout & "content stream not allowed"
• Support resetting response streams teams.py#495 — support resetting response streams (reuse after close())

Streaming error handling (port of #453)

• Add TerminalStreamError, StreamTimedOutError, and StreamNotAllowedError (in types/streamer.ts).
• HttpStream.send() now inspects the 403 response body and maps it to the right error instead of always treating a 403 as canceled:
  • exceeded streaming time → StreamTimedOutError (marks timedOut)
  • cancel → StreamCancelledError
  • not allowed → StreamNotAllowedError
  • anything else / empty body → TerminalStreamError
• On a 2-minute streaming timeout, the stream finalizes by updating the original message in place — it drops the streaminfo entity and stream channelData so the send routes through update (reusing the id) rather than posting a duplicate.
• Chunk sends swallow a timeout mid-stream; close() then sends the buffered content as a plain final message.
• retry gains a nonRetryable option so terminal stream errors are not retried.

Reusable streams (port of #495)

• Emitting or updating after close() reopens the stream on the same instance, starting a new streamed message.
• close() is idempotent until the next emit/update.
• app.process.ts close listener switched from once → on so each reused-stream close fires.

Example

Adds examples/stream, mirroring the teams.py example's final state:

• default message → single-stream demo with suggested actions
• simple-card → sends a minimal Adaptive Card outside the streaming flow
• multi-stream → emits an Adaptive Card as stream 1's final message, close()s, then reuses ctx.stream for a second streamed response

Tests

• packages/apps http-stream spec extended: 403 message→error mapping (parametrized), empty-body 403 → terminal error, final-send timeout updates in place, mid-stream timeout updates in place, and emit-after-close stream reuse.
• Full packages/apps suite passes (294 tests); tsc and eslint clean across the changed library files and the new example.

Notes

• The Python-only uv.lock change was not ported.
• examples/stream/.env is gitignored (no credentials committed).

[Copilot]

Pull request overview

Ports streaming behavior improvements from teams.py into @microsoft/teams.apps, adding richer handling of terminal streaming failures (403 variants), support for reusing a stream instance after close(), and a new examples/stream sample to demonstrate multi-stream flows.

Changes:

• Add terminal streaming error types and route 403 streaming responses to specific errors (timeout/cancel/not-allowed/terminal).
• Make HttpStream.close() idempotent and allow emit/update after close to restart streaming on the same instance; update processor close listener accordingly.
• Add a new examples/stream sample showcasing single-stream, simple-card, and multi-stream usage.

Reviewed changes

Copilot reviewed 13 out of 16 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
packages/apps/src/utils/promises/retry.ts	Adds nonRetryable option to stop retrying specific error classes.
packages/apps/src/types/streamer.ts	Introduces terminal stream error classes and adds closed to the streamer contract.
packages/apps/src/http/http-stream.ts	Implements timeout/not-allowed error mapping, idempotent/reusable close behavior, and finalization behavior after timeout.
packages/apps/src/http/http-stream.spec.ts	Expands test coverage for 403 error mapping, timeout finalization behavior, and stream reuse after close.
packages/apps/src/app.process.ts	Switches close listener to .on('close') to support reused streams firing close multiple times.
examples/stream/turbo.json	Adds turbo task config for the new stream example.
examples/stream/tsconfig.json	Adds TypeScript config for the new stream example.
examples/stream/src/index.ts	Implements the stream demo app (single-stream, simple-card, multi-stream).
examples/stream/README.md	Documents how to run and test the stream example.
examples/stream/package.json	Adds the example package definition and scripts.
examples/stream/eslint.config.js	Adds eslint config wiring for the example.
examples/stream/appPackage/manifest.json	Adds a Teams app manifest for the example bot.
examples/stream/.gitignore	Adds ignore rules for generated/dev files in the example.

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