[Feat] Support audio requests across chat providers

[roomote-roomote]

Opened on behalf of Matt Rubens. Follow up by mentioning @roomote-roomote, in the web UI, or in Slack.

What changed

Added inbound audio and voice-note transcription for Telegram, Discord, and Teams. Each provider now recognizes audio-only task entries and follow-ups, downloads media through its authenticated bounded transport, and appends the shared transcript or actionable warning to the task prompt.

The shared transcription layer normalizes provider MIME metadata and owns consistent transcript, unsupported-model, oversized-media, and failure messages. Extension inference is limited to absent or generic MIME metadata so explicitly typed video and other non-audio attachments never enter audio transcription. Teams file-download wrappers use their nested content type, filename, or file type so uploaded audio is still recognized correctly. Telegram and Teams attachment downloads also enforce byte limits while streaming rather than buffering an unbounded response.

Why this change was made

Audio requests worked in Slack but were ignored or reduced to unusable attachment placeholders in the other chat providers. This makes voice-driven task entry consistent across supported communication surfaces without exposing provider credentials or signed attachment URLs to agents.

Impact

Users can start tasks and send active follow-ups with Telegram voice/audio messages, Discord audio attachments, and Teams audio attachments, including normal Teams file uploads. Unsupported models, media above 20 MiB, unsupported formats, and download failures remain actionable text instead of producing an empty request, while video uploads retain their explicit media classification.

[roomote-community]

No new code issues found. See task

• Video MIME types can be relabeled as audio by filename fallback (packages/cloud-agents/src/server/audio-transcription.ts:55).
• Teams file-download audio attachments are ignored because their wrapper MIME type disables filename inference (packages/communication/src/teams-activity.ts:590).

_{Reviewed f2f73c2}

[roomote-roomote]

Addressed the Teams file-download wrapper feedback in f2f73c2. Wrapper attachments now use nested MIME, filename, or fileType metadata to recognize uploaded audio, while explicit nested video MIME types remain excluded. Targeted tests and the full pre-push checks pass.