Problem statement

OpenSRE currently has no Trello integration. Teams that use Trello for task and incident tracking cannot automatically create or update cards from investigation findings, leaving a manual gap between investigation results and follow-up action items.

Proposed solution

Add a first-class Trello integration that supports:

• onboarding, authentication (API key + token), and connectivity verification
• creating Trello cards from investigation findings with root cause, evidence, and recommended actions
• updating existing cards when follow-up investigations produce new findings
• mapping investigation severity to Trello labels or list positions
• querying existing boards for incident-related context during investigations

Acceptance criteria

• the integration is usable from the investigation workflow end to end
• setup and usage are documented clearly
• the implementation is backed by end-to-end tests in tests/e2e or equivalent
• the PR includes a screen video showing setup plus a successful investigation flow using Trello
• vibecoding without testing will not be allowed; PRs without working end-to-end coverage and screen-video proof should be rejected