perf(state): exclude cron sessions from trigram FTS

hermes_state_schema.py

@@ -414,6 +414,44 @@ class SessionSchemaMixin:
                 exc_info=True,
             )
 
+    def _migrate_trigram_cron_exclusion(self, cursor: sqlite3.Cursor) -> bool:
+        """Install the cron-filtered trigram view and purge historical rows.
+
+        Legacy inline indexes remain opt-in: their content is private to the
+        virtual table and cannot adopt this external-content view. For an
+        external layout, replacing the view and triggers is cheap, but the
+        existing inverted index still contains cron rows until FTS5 rebuilds
+        from the new view. Run that rebuild under the shared cross-process
+        admission gate used by every startup FTS repair.
+        """
+        if self._db_has_legacy_inline_fts(cursor):
+            return True
+        trigram_exists = self._fts_table_probe(cursor, "messages_fts_trigram")
+        if trigram_exists is not True:
+            # Let the normal ensure path create/backfill a missing optional
+            # trigram table. ``None`` means this runtime cannot safely inspect
+            # an existing one, so leave the schema version behind for retry.
+            return trigram_exists is False
+        for name in _FTS_TRIGRAM_TRIGGERS:
+            cursor.execute(f"DROP TRIGGER IF EXISTS {name}")
+        cursor.execute("DROP VIEW IF EXISTS messages_fts_trigram_src")
+        if not self._ensure_fts_schema(
+            cursor, "messages_fts_trigram", FTS_TRIGRAM_SQL
+        ):
+            return False
+        # Always rebuild while schema_version is behind, even if the view
+        # already has the new predicate. A process can die after replacing the
+        # view but before rebuilding/stamping; view text alone cannot prove the
+        # old cron postings were purged.
+        self._run_admitted_startup_rebuild(
+            cursor,
+            lambda: cursor.execute(
+                "INSERT INTO messages_fts_trigram(messages_fts_trigram) "
+                "VALUES('rebuild')"
+            ),
+        )
+        return True
+
 
     @staticmethod
     def _rebuild_fts_indexes(
@@ -1490,6 +1528,15 @@ class SessionSchemaMixin:
                 # rows, but clear migrated rows so future writes do not keep
                 # one large prompt copy per session.
                 self._dedupe_legacy_system_prompts(cursor)
+            if current_version < 29 and fts5_available:
+                # v29 (was v27 in the original PR; main had already reached
+                # v28 with column-reconciliation bumps, so a `< 27` gate would
+                # never fire on existing installs): cron sessions remain canonical and stay in the standard
+                # word index, but no longer inflate the trigram substring index.
+                # Rebuild once so rows indexed by older trigger/view definitions
+                # do not survive indefinitely as stale matches and disk usage.
+                if not self._migrate_trigram_cron_exclusion(cursor):
+                    fts_migrations_complete = False
 
             # The FTS storage layout is versioned independently of the main
             # schema (see the v23 note above). Stamp the current layout so the