feat: add plugin worker protocol, bootstrap and plugin_storage table

Worker-side ctx proxy plus the message envelope it talks over, and the
per-plugin key/value table behind ctx.storage with migrations for all
three dialects. Rows cascade with the plugin so uninstalling leaves
nothing behind.

drizzle/mysql/0024_thin_colleen_wing.sql

@@ -0,0 +1,11 @@
+CREATE TABLE `plugin_storage` (
+	`id` int AUTO_INCREMENT NOT NULL,
+	`plugin_id` varchar(255) NOT NULL,
+	`key` varchar(255) NOT NULL,
+	`value` text NOT NULL,
+	`updated_at` varchar(255) NOT NULL DEFAULT (CURRENT_TIMESTAMP),
+	CONSTRAINT `plugin_storage_id` PRIMARY KEY(`id`),
+	CONSTRAINT `idx_plugin_storage_plugin_key` UNIQUE(`plugin_id`,`key`)
+);
+--> statement-breakpoint
+ALTER TABLE `plugin_storage` ADD CONSTRAINT `plugin_storage_plugin_id_plugins_id_fk` FOREIGN KEY (`plugin_id`) REFERENCES `plugins`(`id`) ON DELETE cascade ON UPDATE no action;

drizzle/mysql/meta/_journal.json

@@ -169,6 +169,13 @@
       "when": 1789751455875,
       "tag": "0023_even_beast",
       "breakpoints": true
+    },
+    {
+      "idx": 24,
+      "version": "5",
+      "when": 1789991404402,
+      "tag": "0024_thin_colleen_wing",
+      "breakpoints": true
     }
   ]
 }