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/project-command.model.test.ts

@@ -74,20 +74,22 @@ describe("serialized project commands", () => {
   });
 
   it("rejects values that JSON would lose or silently change", () => {
-    const invalidPayloads: unknown[] = [
-      { value: undefined },
-      { value: Number.NaN },
-      { value: Number.POSITIVE_INFINITY },
-      { value: new Date() },
+    const invalidPayloads: Array<[unknown, RegExp]> = [
+      [{ value: undefined }, /must contain JSON values only/],
+      [{ value: Number.NaN }, /numbers must be finite/],
+      [{ value: Number.POSITIVE_INFINITY }, /numbers must be finite/],
+      [{ value: new Date() }, /must contain plain objects only/],
     ];
 
-    for (const payload of invalidPayloads) {
-      assert.throws(() =>
-        serializeProjectCommand({
-          schemaVersion: 1,
-          type: "test.invalid",
-          payload: payload as never,
-        })
+    for (const [payload, expectedError] of invalidPayloads) {
+      assert.throws(
+        () =>
+          serializeProjectCommand({
+            schemaVersion: 1,
+            type: "test.invalid",
+            payload: payload as never,
+          }),
+        expectedError
       );
     }
   });