feat: add custom SQL handling for triggers and virtual tables

- Introduced a new method `runCustomMigrations` in `DbService` to execute custom SQL statements that Drizzle cannot manage, such as triggers and virtual tables.
- Updated `database-patterns.md` and `README.md` to document the handling of custom SQL and its importance in maintaining database integrity during migrations.
- Refactored `messageFts.ts` to define FTS5 virtual table and associated triggers as idempotent SQL statements for better migration management.

migrations/sqlite-drizzle/meta/_journal.json

@@ -9,12 +9,12 @@
       "when": 1767272575118
     },
     {
+      "breakpoints": true,
       "idx": 1,
-      "version": "6",
-      "when": 1767455592181,
       "tag": "0001_futuristic_human_fly",
-      "breakpoints": true
+      "version": "6",
+      "when": 1767455592181
     }
   ],
   "version": "7"
-}
+}