Add identifier column to plugins table for cleaner plugin lookup

- Added 'identifier' column (unique) for machine-readable plugin ID
- 'name' now used for display name only
- Updated trial-execution to look up by identifier first, then name
- Added migration script for existing databases

scripts/seed-dev.ts

@@ -159,6 +159,7 @@ async function main() {
       .insert(schema.plugins)
       .values({
         robotId: naoRobot!.id,
+        identifier: NAO_PLUGIN_DEF.robotId,
         name: NAO_PLUGIN_DEF.name,
         version: NAO_PLUGIN_DEF.version,
         description: NAO_PLUGIN_DEF.description,