[021] Implement IPC bridge for agent events and UI notifications

[konard]

Parent epic: #1

Phase: Teleton Agent Integration
Priority: 21

Scope

Create a WebSocket or HTTP IPC bridge that lets UI layers exchange messages, tasks, and consent requests with Teleton Agent.

Implementation Steps

• Define IPC message envelopes and versioning.
• Implement request, event, error, and cancellation flows.
• Add contract tests using a local mock bridge.

Acceptance Criteria

• IPC contract supports incoming message hooks and agent action proposals.
• UI can distinguish informational updates from confirmation-required actions.
• Malformed messages are rejected and tested.

Automation

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