Polish off all our gross edges around frontend/backend Public name management

frontend/src/test/chatHeaderKeyVisibility.test.tsx

@@ -3,6 +3,7 @@ import { describe, expect, it, vi } from 'vitest';
 
 import { ChatHeader } from '../components/ChatHeader';
 import type { Channel, Contact, Conversation, Favorite, PathDiscoveryResponse } from '../types';
+import { PUBLIC_CHANNEL_KEY } from '../utils/publicChannel';
 
 function makeChannel(key: string, name: string, isHashtag: boolean): Channel {
   return { key, name, is_hashtag: isHashtag, on_radio: false, last_read_at: null };
@@ -169,6 +170,25 @@ describe('ChatHeader key visibility', () => {
     expect(onToggleNotifications).toHaveBeenCalledTimes(1);
   });
 
+  it('hides the delete button for the canonical Public channel', () => {
+    const channel = makeChannel(PUBLIC_CHANNEL_KEY, 'Public', false);
+    const conversation: Conversation = { type: 'channel', id: PUBLIC_CHANNEL_KEY, name: 'Public' };
+
+    render(<ChatHeader {...baseProps} conversation={conversation} channels={[channel]} />);
+
+    expect(screen.queryByRole('button', { name: 'Delete' })).not.toBeInTheDocument();
+  });
+
+  it('still shows the delete button for non-canonical channels named Public', () => {
+    const key = 'AB'.repeat(16);
+    const channel = makeChannel(key, 'Public', false);
+    const conversation: Conversation = { type: 'channel', id: key, name: 'Public' };
+
+    render(<ChatHeader {...baseProps} conversation={conversation} channels={[channel]} />);
+
+    expect(screen.getByRole('button', { name: 'Delete' })).toBeInTheDocument();
+  });
+
   it('opens path discovery modal for contacts and runs the request on demand', async () => {
     const pubKey = '21'.repeat(32);
     const contact: Contact = {

frontend/src/test/sidebar.test.tsx

@@ -4,6 +4,7 @@ import { beforeEach, describe, expect, it, vi } from 'vitest';
 import { Sidebar } from '../components/Sidebar';
 import { CONTACT_TYPE_REPEATER, type Channel, type Contact, type Favorite } from '../types';
 import { getStateKey, type ConversationTimes } from '../utils/conversationState';
+import { PUBLIC_CHANNEL_KEY } from '../utils/publicChannel';
 
 function makeChannel(key: string, name: string): Channel {
   return {
@@ -316,4 +317,38 @@ describe('Sidebar section summaries', () => {
     expect(getContactsOrder()).toEqual(['Zed', 'Amy']);
     expect(getRepeatersOrder()).toEqual(['Zulu Relay', 'Alpha Relay']);
   });
+
+  it('pins only the canonical Public channel to the top of channel sorting', () => {
+    const publicChannel = makeChannel(PUBLIC_CHANNEL_KEY, 'Public');
+    const fakePublic = makeChannel('DD'.repeat(16), 'Public');
+    const alphaChannel = makeChannel('CC'.repeat(16), '#alpha');
+    const onSelectConversation = vi.fn();
+
+    render(
+      <Sidebar
+        contacts={[]}
+        channels={[fakePublic, alphaChannel, publicChannel]}
+        activeConversation={null}
+        onSelectConversation={onSelectConversation}
+        onNewMessage={vi.fn()}
+        lastMessageTimes={{}}
+        unreadCounts={{}}
+        mentions={{}}
+        showCracker={false}
+        crackerRunning={false}
+        onToggleCracker={vi.fn()}
+        onMarkAllRead={vi.fn()}
+        favorites={[]}
+        legacySortOrder="alpha"
+      />
+    );
+
+    fireEvent.click(screen.getAllByText('Public')[0]);
+
+    expect(onSelectConversation).toHaveBeenCalledWith({
+      type: 'channel',
+      id: PUBLIC_CHANNEL_KEY,
+      name: 'Public',
+    });
+  });
 });

frontend/src/test/urlHash.test.ts

@@ -13,6 +13,7 @@ import {
   resolveContactFromHashToken,
 } from '../utils/urlHash';
 import type { Channel, Contact } from '../types';
+import { PUBLIC_CHANNEL_KEY } from '../utils/publicChannel';
 
 describe('parseHashConversation', () => {
   let originalHash: string;
@@ -149,7 +150,7 @@ describe('parseHashConversation', () => {
 describe('resolveChannelFromHashToken', () => {
   const channels: Channel[] = [
     {
-      key: 'ABCDEF0123456789ABCDEF0123456789',
+      key: PUBLIC_CHANNEL_KEY,
       name: 'Public',
       is_hashtag: false,
       on_radio: true,
@@ -172,13 +173,13 @@ describe('resolveChannelFromHashToken', () => {
   ];
 
   it('prefers stable key lookup (case-insensitive)', () => {
-    const result = resolveChannelFromHashToken('abcdef0123456789abcdef0123456789', channels);
-    expect(result?.key).toBe('ABCDEF0123456789ABCDEF0123456789');
+    const result = resolveChannelFromHashToken(PUBLIC_CHANNEL_KEY.toLowerCase(), channels);
+    expect(result?.key).toBe(PUBLIC_CHANNEL_KEY);
   });
 
-  it('supports legacy name-based hash lookup', () => {
+  it('resolves legacy Public hashes to the canonical Public key', () => {
     const result = resolveChannelFromHashToken('Public', channels);
-    expect(result?.key).toBe('ABCDEF0123456789ABCDEF0123456789');
+    expect(result?.key).toBe(PUBLIC_CHANNEL_KEY);
   });
 
   it('supports legacy hashtag hash without leading #', () => {