feat: enhance login options with read-only and nsec support (#126)

* feat: enhance login options with read-only and nsec support

- Add read-only login mode supporting:
  - npub (bech32 public key)
  - nprofile (bech32 profile with relay hints)
  - hex public key
  - NIP-05 addresses (user@domain.com)

- Add private key (nsec) login with security warning
  - Supports nsec1... format
  - Supports 64-char hex private key
  - Shows prominent security warning about localStorage storage

- Reorganize user menu to show login before theme option

- Use ReadonlyAccount from applesauce-accounts for read-only mode
- Use PrivateKeyAccount from applesauce-accounts for nsec login
- Update LoginDialog with 4 tabs: Extension, Read-Only, Private Key, Remote
- All account types properly registered via registerCommonAccountTypes()

Technical notes:
- ReadonlySigner throws errors on sign/encrypt operations
- Existing components naturally handle accounts without signing capability
- Hub/ActionRunner already syncs with account signers automatically

* feat: add generate identity button to login dialog

- Add "Generate Identity" button above login tabs
- Uses Wand2 icon from lucide-react
- Creates new key pair using PrivateKeyAccount.generateNew()
- Automatically stores nsec in localStorage and sets as active account
- Provides quick onboarding for new users without external wallet setup

* feat: add useAccount hook for signing capability detection

Created a centralized hook to check account signing capabilities and
refactored components to distinguish between signing and read-only operations.

New hook (src/hooks/useAccount.ts):
- Returns account, pubkey, canSign, signer, isLoggedIn
- Detects ReadonlyAccount vs signing accounts
- Provides clear API for checking signing capability

Refactored components:
- ChatViewer: Use canSign for message composer, replying, actions
  - Show "Sign in to send messages" for read-only accounts
  - Disable message input for accounts without signing
- SpellDialog: Use canSign for publishing spells
  - Show clear warning for read-only accounts
  - Updated error messages to mention read-only limitation
- useEmojiSearch: Use pubkey for loading custom emoji lists
  - Works correctly with both signing and read-only accounts

Benefits:
- Clear separation between read (pubkey) and write (canSign, signer) operations
- Read-only accounts can browse, view profiles, load data
- Signing operations properly disabled for read-only accounts
- Consistent pattern across the codebase for account checks
- Better UX with specific messages about account capabilities

---------

Co-authored-by: Claude <noreply@anthropic.com>

src/hooks/useAccount.ts

@@ -0,0 +1,69 @@
+import { useMemo } from "react";
+import { use$ } from "applesauce-react/hooks";
+import accounts from "@/services/accounts";
+
+/**
+ * Hook to access the active account with signing capability detection
+ *
+ * @returns {object} Account state
+ * @property {IAccount | undefined} account - The full active account object
+ * @property {string | undefined} pubkey - The account's public key (available for all account types)
+ * @property {boolean} canSign - Whether the account can sign events (false for read-only accounts)
+ * @property {ISigner | undefined} signer - The signer instance (undefined for read-only accounts)
+ * @property {boolean} isLoggedIn - Whether any account is active (including read-only)
+ *
+ * @example
+ * // For read-only operations (viewing profiles, loading data)
+ * const { pubkey, isLoggedIn } = useAccount();
+ * if (pubkey) {
+ *   // Load user's relay list, emoji list, etc.
+ * }
+ *
+ * @example
+ * // For signing operations (posting, publishing, uploading)
+ * const { canSign, signer, pubkey } = useAccount();
+ * if (canSign) {
+ *   // Can publish events
+ *   await adapter.sendMessage({ activePubkey: pubkey, activeSigner: signer, ... });
+ * } else {
+ *   // Show "log in to post" message
+ * }
+ */
+export function useAccount() {
+  const account = use$(accounts.active$);
+
+  return useMemo(() => {
+    if (!account) {
+      return {
+        account: undefined,
+        pubkey: undefined,
+        canSign: false,
+        signer: undefined,
+        isLoggedIn: false,
+      };
+    }
+
+    // Check if the account has a functional signer
+    // Read-only accounts have a signer that throws errors on sign operations
+    // We detect this by checking for the ReadonlySigner type or checking signer methods
+    const signer = account.signer;
+    let canSign = false;
+
+    if (signer) {
+      // ReadonlyAccount from applesauce-accounts has a ReadonlySigner
+      // that throws on signEvent, nip04, nip44 operations
+      // We can detect it by checking if it's an instance with the expected methods
+      // but we'll use a safer approach: check the account type name
+      const accountType = account.constructor.name;
+      canSign = accountType !== "ReadonlyAccount";
+    }
+
+    return {
+      account,
+      pubkey: account.pubkey,
+      canSign,
+      signer: canSign ? signer : undefined,
+      isLoggedIn: true,
+    };
+  }, [account]);
+}

src/hooks/useEmojiSearch.ts

@@ -1,13 +1,12 @@
 import { useEffect, useMemo, useRef } from "react";
-import { use$ } from "applesauce-react/hooks";
 import {
   EmojiSearchService,
   type EmojiSearchResult,
 } from "@/services/emoji-search";
 import { UNICODE_EMOJIS } from "@/lib/unicode-emojis";
 import eventStore from "@/services/event-store";
-import accounts from "@/services/accounts";
 import type { NostrEvent } from "@/types/nostr";
+import { useAccount } from "./useAccount";
 
 /**
  * Hook to provide emoji search functionality with automatic indexing
@@ -15,7 +14,7 @@ import type { NostrEvent } from "@/types/nostr";
  */
 export function useEmojiSearch(contextEvent?: NostrEvent) {
   const serviceRef = useRef<EmojiSearchService | null>(null);
-  const activeAccount = use$(accounts.active$);
+  const { pubkey } = useAccount();
 
   // Create service instance (singleton per component mount)
   if (!serviceRef.current) {
@@ -35,12 +34,10 @@ export function useEmojiSearch(contextEvent?: NostrEvent) {
 
   // Subscribe to user's emoji list (kind 10030) and emoji sets (kind 30030)
   useEffect(() => {
-    if (!activeAccount?.pubkey) {
+    if (!pubkey) {
       return;
     }
 
-    const pubkey = activeAccount.pubkey;
-
     // Subscribe to user's emoji list (kind 10030 - replaceable)
     const userEmojiList$ = eventStore.replaceable(10030, pubkey);
     const userEmojiSub = userEmojiList$.subscribe({
@@ -99,7 +96,7 @@ export function useEmojiSearch(contextEvent?: NostrEvent) {
       // Clear custom emojis but keep unicode
       service.clearCustom();
     };
-  }, [activeAccount?.pubkey, service]);
+  }, [pubkey, service]);
 
   // Memoize search function
   const searchEmojis = useMemo(