Add zaps: NWC wallet connect + NIP-57 zap flow

- NWC client (nwc.ts): parse URI, encrypt/send kind 23194, await kind 23195 response
- Lightning store: persist NWC URI to localStorage, zap() via NDKZapper + lnPay callback
- ZapModal: amount presets (21/100/500/1000/5000 sats), custom amount, optional comment,
  paying/success/error states, prompts to Settings if no wallet connected
- ⚡ zap button on NoteCard (action row) and ProfileView (header, next to follow)
- Settings > Lightning Wallet section: paste NWC URI, connect/disconnect

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/stores/lightning.ts

@@ -0,0 +1,82 @@
+import { create } from "zustand";
+import { NDKEvent, NDKUser, NDKZapper, LnPayCb } from "@nostr-dev-kit/ndk";
+import { getNDK } from "../lib/nostr";
+import { payInvoiceViaNWC, isValidNwcUri } from "../lib/lightning/nwc";
+
+const NWC_STORAGE_KEY = "wrystr_nwc_uri";
+
+interface ZapTarget {
+  type: "note";
+  event: NDKEvent;
+  recipientPubkey: string;
+  recipientLud16?: string;
+}
+
+interface ZapProfileTarget {
+  type: "profile";
+  pubkey: string;
+  lud16?: string;
+}
+
+export type ZapTargetSpec = ZapTarget | ZapProfileTarget;
+
+interface LightningState {
+  nwcUri: string | null;
+  setNwcUri: (uri: string) => void;
+  clearNwcUri: () => void;
+  zap: (target: ZapTargetSpec, amountSats: number, comment?: string) => Promise<void>;
+}
+
+export const useLightningStore = create<LightningState>(() => ({
+  nwcUri: localStorage.getItem(NWC_STORAGE_KEY),
+
+  setNwcUri: (uri: string) => {
+    if (!isValidNwcUri(uri)) throw new Error("Invalid NWC URI");
+    localStorage.setItem(NWC_STORAGE_KEY, uri);
+    useLightningStore.setState({ nwcUri: uri });
+  },
+
+  clearNwcUri: () => {
+    localStorage.removeItem(NWC_STORAGE_KEY);
+    useLightningStore.setState({ nwcUri: null });
+  },
+
+  zap: async (targetSpec: ZapTargetSpec, amountSats: number, comment?: string) => {
+    const { nwcUri } = useLightningStore.getState();
+    if (!nwcUri) throw new Error("No wallet connected. Add an NWC connection in Settings.");
+
+    const ndk = getNDK();
+    if (!ndk.signer) throw new Error("Not logged in");
+
+    let target: NDKEvent | NDKUser;
+    if (targetSpec.type === "note") {
+      target = targetSpec.event;
+    } else {
+      target = ndk.getUser({ pubkey: targetSpec.pubkey });
+    }
+
+    const lnPay: LnPayCb = async ({ pr }) => {
+      const preimage = await payInvoiceViaNWC(nwcUri, pr);
+      return { preimage };
+    };
+
+    const zapper = new NDKZapper(target, amountSats * 1000, "msat", {
+      comment,
+      lnPay,
+      ndk,
+    });
+
+    return new Promise((resolve, reject) => {
+      zapper.on("complete", (results) => {
+        const errors = Array.from(results.values()).filter((r) => r instanceof Error);
+        if (errors.length > 0) {
+          reject(errors[0]);
+        } else {
+          resolve();
+        }
+      });
+
+      zapper.zap().catch(reject);
+    });
+  },
+}));