Preflight deploy review: channel_installation dropped the workspace/agent FK (MUL-3515 §4), so unlike lark_installation it does not cascade away when its workspace is deleted or its agent is hard-deleted (e.g. runtime teardown). The hub-boot query then keeps opening a WebSocket for a bot whose owner is gone.
JOIN ListActiveChannelInstallations to live workspace + agent so an orphaned installation is never connected, uniformly for every deletion path. The JOIN matches the old ON DELETE CASCADE semantics (row existence, not agent archival), so an archived-but-present agent's installation is still listed; the orphaned row's encrypted secret is thereby never decrypted/used.
Tests: a real-DB handler test asserts a deleted-workspace/agent installation and a non-Feishu one are both excluded; the lark scope test's active-list assertion moved there since the JOIN now needs real workspace/agent fixtures. (Physically deleting dormant orphaned channel rows on workspace/agent deletion is a separate app-layer-cleanup follow-up.)
MUL-3515
Co-authored-by: multica-agent <github@multica.ai>
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