feat: Add errands schema, repository, and wire into tRPC context/container

Creates the errands table (with conflictFiles column), errand-repository
port interface, DrizzleErrandRepository adapter, and wires the repository
into TRPCContext, the DI container, _helpers.ts requireErrandRepository guard,
and the test harness. Also fixes pre-existing TS error in controller.test.ts.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/server/drizzle/0034_salty_next_avengers.sql

@@ -0,0 +1,17 @@
+CREATE TABLE `errands` (
+	`id` text PRIMARY KEY NOT NULL,
+	`description` text NOT NULL,
+	`branch` text NOT NULL,
+	`base_branch` text DEFAULT 'main' NOT NULL,
+	`agent_id` text,
+	`project_id` text NOT NULL,
+	`status` text DEFAULT 'active' NOT NULL,
+	`created_at` integer NOT NULL,
+	`updated_at` integer NOT NULL,
+	`conflict_files` text,
+	FOREIGN KEY (`agent_id`) REFERENCES `agents`(`id`) ON UPDATE no action ON DELETE set null,
+	FOREIGN KEY (`project_id`) REFERENCES `projects`(`id`) ON UPDATE no action ON DELETE cascade
+);
+--> statement-breakpoint
+CREATE INDEX `errands_project_id_idx` ON `errands` (`project_id`);--> statement-breakpoint
+CREATE INDEX `errands_status_idx` ON `errands` (`status`);

apps/server/drizzle/meta/_journal.json

@@ -239,6 +239,13 @@
       "when": 1772409600000,
       "tag": "0033_drop_approval_columns",
       "breakpoints": true
+    },
+    {
+      "idx": 34,
+      "version": "6",
+      "when": 1772808163349,
+      "tag": "0034_salty_next_avengers",
+      "breakpoints": true
     }
   ]
 }