Tighten rejection tests to their expected errors

Every assert.throws now names the error it expects, so a broken fixture
or an unrelated failure can no longer satisfy a rejection test. Zod
rejections are matched by issue path and code via tests/support/zod-assertions.ts.

Restore snapshot coverage lost with the release baseline: invalid board
floor, room floor and circuit section references and a reserve state
that contradicts the device rows are rejected again under test.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/batched-insert.persistence.test.ts

@@ -13,7 +13,10 @@ describe("batched SQLite inserts", () => {
       migrate(context.db, { migrationsFolder: path.resolve("src", "db", "migrations") });
       const values = Array.from({ length: 401 }, (_, index) => ({ id: `project-${index}`, name: `Projekt ${index}` }));
       values[400] = { id: "project-0", name: "Duplikat" };
-      assert.throws(() => context.db.transaction((tx) => insertManyInBatches(tx, projects, values)));
+      assert.throws(
+        () => context.db.transaction((tx) => insertManyInBatches(tx, projects, values)),
+        /UNIQUE constraint failed: projects\.id/
+      );
       assert.equal(context.db.select().from(projects).all().length, 0);
     } finally { context.close(); }
   });