chore(plugins): add [integrity] SHA-256 hashes for all hook scripts

The daemon's `manifest_missing_integrity_hooks` check (#3804) hard-fails
any registry install whose plugin.toml declares hooks but lacks an
[integrity] entry for each one. All 11 plugins under plugins/ had the
[hooks] table but were missing [integrity], so `librefang plugin install
<name>` would error after download with "missing [integrity] hashes for
hook script(s): ...".

Compute and pin SHA-256 over each `hooks/*.py` under every plugin dir.
The mempalace-indexer entries were already present and are unchanged
(reordered alphabetically by the regenerator).

Verified each plugin.toml still parses (Python tomllib).

plugins/auto-summarizer/plugin.toml

@@ -35,3 +35,7 @@ description = "Mantiene un resumen continuo de la conversación para que los age
 [i18n.fr]
 name = "Auto-résumé"
 description = "Maintient un résumé continu de la conversation pour que les agents ne perdent pas de contexte dans les longs échanges."
+
+[integrity]
+"hooks/after_turn.py" = "fe24d5f8dd85348f855f7e2c27e607e57c4fad549d50d814101be14fa5ab34f1"
+"hooks/ingest.py" = "0581dd415457bffc3160580acf3036a2fe9e211e86b49bbc51cc30118dc67e0e"