feat(chat): Hazel channels as alert destinations through the bot - #2027

🟢 Confidence 10/10 · safe to merge. A contained connector change: one new reader through the existing client-span and error-mapping helpers, pinned by three transport tests.
_{no findings · tests covered · risk medium · 1/1 new units observable}

Hazel's transport now lists the bot's channels from GET /organizations/{id}/bot-channels, so Hazel channels become ordinary chat alert destinations; the manifest description and connector README follow. The change reuses the existing request, decode and failure-mapping helpers and is safe to merge.

• hazelOutbound.destinations reads Hazel's bot-channels endpoint instead of answering empty
• Manifest description and README now cover alerts and the channels:read scope

Before merge

• Manual · Ship Hazel's bot-channels endpoint (MapleTechLabs/hazel#372) before this deploys; without it the picker fails
• Manual · Add channels:read to the US and EU Hazel bots, or every channel listing answers auth

Production impact

_{5b4006d · Reply "won't fix" to dismiss a finding, or mention @maple-review-bot to ask about one.}