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/topic-memory/plugin.toml

@@ -35,3 +35,7 @@ description = "Recuerdo de memoria consciente del tema con agrupamiento de palab
 [i18n.fr]
 name = "Mémoire par sujets"
 description = "Rappel de mémoire orienté sujet avec clustering de mots-clés pour un contexte inter-conversations."
+
+[integrity]
+"hooks/after_turn.py" = "d2a52d8070250c6308de1af8739dfee0691b4dc73ee45448f32b7ed446645d28"
+"hooks/ingest.py" = "9ee56481f5b7039a12d4a6f373b7f54af7ead8f790995280551739658997cc0f"