fix: persist environment selection in Zustand store instead of URL params

Environment selector was losing its value on navigation because URL search
params were silently dropped by navigate() calls. Moved to a Zustand store
with localStorage persistence so the selection survives navigation, page
refresh, and new tabs. Switching environment now resets all filters, clears
URL params, invalidates queries, and remounts pages via Outlet key. Also
syncs openapi.json schema with running backend.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/api/environment-store.ts

@@ -0,0 +1,20 @@
+import { create } from 'zustand';
+
+const STORAGE_KEY = 'cameleer-environment';
+
+interface EnvironmentState {
+  environment: string | undefined;
+  setEnvironment: (env: string | undefined) => void;
+}
+
+export const useEnvironmentStore = create<EnvironmentState>((set) => ({
+  environment: localStorage.getItem(STORAGE_KEY) || undefined,
+  setEnvironment: (env) => {
+    if (env) {
+      localStorage.setItem(STORAGE_KEY, env);
+    } else {
+      localStorage.removeItem(STORAGE_KEY);
+    }
+    set({ environment: env });
+  },
+}));