V194: withholds the integration connection bodies the settings history has already recorded.

The settings history (V184, 2.16.0) writes a permanent setting.changed activity entry for every settings write, with the value before and after — except for restricted settings, whose values it withholds. It decided what was restricted by key name alone. Integration connection rows are keyed by their own uuid, and their JSON body holds the connection's tokens (in plain text when integration encryption is off), so every connect and every token refresh wrote the whole body into an entry that is never pruned and that the admin Activity page shows to anyone who can open it. A rotated or revoked token stayed readable there for good.

The writer no longer does this (PhoenixKit.Settings.secret_setting?/2). This migration withholds what it already wrote, exactly as a restricted setting is recorded: from and to become null and restricted true. The rest of each entry — who, when, which row — stays, so the history still says that the connection changed.

An entry belongs to an integration row when any of these holds:

• its key is the row's own uuid (metadata.key equals the entry's resource_uuid) — only integration rows are keyed that way, and this still recognises rows deleted since;
• its key has the legacy integration: prefix;
• a settings row with that key has module = 'integrations'.

Re-runnable: an entry already restricted is left alone.

down/1

Moves the version marker back and nothing else. The withheld values are gone on purpose; restoring them is the defect this version removes.