Typecheck the test tree, and fix what it found

server/tsconfig.json has include: ["src"], so tests/ was never typechecked.
A service that gained a constructor parameter did not break its hand-wired
call sites at compile time — the argument arrived as undefined and threw at
runtime, if anything read it at all. The notifications sweep hit 46 such
sites and only a stash-diff against a throwaway tsconfig found them.

tsconfig.tests.json makes that permanent. It is not wired into CI yet: the
tree still reports 170 errors, and turning it on now would block every
unrelated PR.

Three of the first fixes were not type noise.

DAY-SVC-034 asserted that createAccommodation rolls back a failed
reservation insert. That method moved to AccommodationsService in the
days/accommodations split, so the case was calling undefined — which throws,
which satisfied .toThrow(). The rollback has been unchecked ever since,
while the case reported green. Repointed at the owner; the invariant holds.

host-rpc.test.ts typed its response as RpcResponse & Partial<RpcError>.
Both carry ok, one as true and one as false, so the intersection is never
and all 97 property reads in the file were errors nobody could see.

auth.controller.test.ts passes {} as the body in cases that stub the service
and assert on the mapping around it. That is correct as written — the point
of several of them is that the error path never reads the body — so anyBody()
names the intent instead of inventing fields the assertions do not read.
Three changePassword calls were genuinely missing the @Res() argument.

server/tests/unit/plugins/host-rpc.test.ts

@@ -102,7 +102,21 @@ const registry = createTestPluginRegistry([
 const factory = new PluginRpcHostFactory(dbs, registry as unknown as PluginRpcRegistryService);
 const stubRouter: PluginCallRouter = { callPlugin: async () => undefined, emitPluginEvent: () => {} };
 const makeHost = (id: string, ...perms: string[]) => factory.create(id, new Set(perms), stubRouter);
-type Res = RpcResponse & Partial<RpcError>;
+/**
+ * A response read loosely, on purpose.
+ *
+ * `RpcResponse & Partial<RpcError>` collapsed to `never`: both carry `ok`, one
+ * as the literal `true` and the other as `false`, so the intersection has no
+ * inhabitant and every `.ok` / `.result` / `.error` below was an error the
+ * build never saw, because tests/ sits outside tsconfig's include. The union
+ * would be the honest runtime type, but `dispatch` here is asserted on from
+ * both sides in the same expression, so this widens instead of narrowing.
+ */
+type Res = Pick<RpcResponse, 'k' | 'id'> & {
+  ok: boolean;
+  result?: unknown;
+  error?: RpcError['error'];
+};
 // The acting user is a REST arg, not a defaulted one: an explicit `undefined` has to
 // stay undefined (that is the userless-context case), and a default parameter would
 // quietly turn it back into user 5.