refactor: route/schema consistency (parseId, broad invalidation, Czech messages, Zod 4 strictObject)

- OfferDetail: invalidate broad ["offers"] not ["offers","list"] (CLAUDE.md convention)
- trips.ts/sessions.ts: use parseId helper (validated 400) instead of raw parseInt for route ids
- audit-log.ts: z.object().strict() -> z.strictObject() (Zod 4 idiom)
- attendance.ts, orders/offers schemas: English user-facing strings -> Czech
- project-files.ts: unify 'not found' phrasing to the codebase-dominant 'nenalezen' form

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/routes/admin/sessions.ts

@@ -1,7 +1,7 @@
 import { FastifyInstance } from "fastify";
 import prisma from "../../config/database";
 import { requireAuth } from "../../middleware/auth";
-import { success, error } from "../../utils/response";
+import { success, error, parseId } from "../../utils/response";
 import { hashToken } from "../../services/auth";
 
 /** Parse user-agent string into browser, OS, and device icon */
@@ -81,8 +81,8 @@ export default async function sessionsRoutes(
     "/:id",
     { preHandler: requireAuth },
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (Number.isNaN(id)) return error(reply, "Neplatné ID relace", 400);
+      const id = parseId((request.params as any).id, reply);
+      if (id === null) return;
       const authData = request.authData!;
 
       const session = await prisma.refresh_tokens.findFirst({