ui : route new-chat entry points through tabs

The sidebar New chat item, Cmd+Shift+O, the search page and the
arrow-key fallback now open a new-chat tab instead of navigating to the
?new_chat URL, which is removed. New chat is no longer a special route
but a tab like any other conversation.

tools/ui/src/lib/components/app/navigation/SidebarNavigation/SidebarNavigationActions.svelte

@@ -12,7 +12,7 @@
 		SIDEBAR_ACTIONS_ITEMS
 	} from '$lib/constants';
 	import { TooltipSide } from '$lib/enums';
-	import { deviceStore } from '$lib/stores';
+	import { conversationsStore, deviceStore } from '$lib/stores';
 	import type { Component } from 'svelte';
 	import { onMount } from 'svelte';
 	import { circIn } from 'svelte/easing';
@@ -109,14 +109,20 @@
 			{@const isActive = isItemActive(item)}
 			{@const isSearchOnMobile = item.icon === Search && deviceStore.isMobile}
 			{@const itemHref = isSearchOnMobile ? ROUTES.SEARCH : item.route}
-			{@const itemOnClick = item.route
-				? () => {
-						onNewChat?.();
-						goto(item.route!);
-					}
-				: isSearchOnMobile
-					? undefined
-					: onSearchClick}
+			{@const itemOnClick =
+				item.action === 'new-chat'
+					? () => {
+							onNewChat?.();
+							conversationsStore.openNewChatTab();
+						}
+					: item.route
+						? () => {
+								onNewChat?.();
+								goto(item.route!);
+							}
+						: isSearchOnMobile
+							? undefined
+							: onSearchClick}
 			{@const itemTransition = {
 				delay: !initialized ? i * ICON_STRIP_TRANSITION_DELAY_MULTIPLIER : 0,
 				duration: ICON_STRIP_TRANSITION_DURATION,
@@ -157,14 +163,20 @@
 		{#each SIDEBAR_ACTIONS_ITEMS as item, i (item.tooltip)}
 			{@const isActive = isItemActive(item)}
 			{@const isSearchOnMobile = item.icon === Search && deviceStore.isMobile}
-			{@const itemOnClick = item.route
-				? () => {
-						onNewChat?.();
-						goto(item.route!);
-					}
-				: isSearchOnMobile
-					? undefined
-					: onSearchClick}
+			{@const itemOnClick =
+				item.action === 'new-chat'
+					? () => {
+							onNewChat?.();
+							conversationsStore.openNewChatTab();
+						}
+					: item.route
+						? () => {
+								onNewChat?.();
+								goto(item.route!);
+							}
+						: isSearchOnMobile
+							? undefined
+							: onSearchClick}
 			{@const itemTransition = {
 				delay: !initialized ? i * ICON_STRIP_TRANSITION_DELAY_MULTIPLIER : 0,
 				duration: ICON_STRIP_TRANSITION_DURATION,

tools/ui/src/lib/constants/routes.constants.ts

@@ -4,8 +4,6 @@ export const URL_PARAMS = {
 	LOAD: 'load',
 	/** Model to select. */
 	MODEL: 'model',
-	/** Start a new chat. */
-	NEW_CHAT: 'new_chat',
 	/** Prompt to send on arrival. */
 	QUERY: 'q'
 } as const;
@@ -15,8 +13,6 @@ export const ROUTES = {
 	CHAT: '#/chat',
 	/** MCP servers. */
 	MCP_SERVERS: '#/mcp-servers',
-	/** New chat — root with new chat query param. */
-	NEW_CHAT: `?${URL_PARAMS.NEW_CHAT}=true#/`,
 	/** Search — mobile-only full-page conversation search. */
 	SEARCH: '#/search',
 	/** Settings base — for dynamic settings URLs use RouterService. */

tools/ui/src/lib/constants/ui.constants.ts

@@ -55,7 +55,7 @@ export const ICON_STRIP_TRANSITION_DELAY_MULTIPLIER = 50;
 export const MAX_HEIGHT_CODE_BLOCK = '22rem';
 
 export const SIDEBAR_ACTIONS_ITEMS: DesktopIconStripItem[] = [
-	{ icon: SquarePen, keys: ['shift', 'cmd', 'o'], route: ROUTES.NEW_CHAT, tooltip: 'New chat' },
+	{ action: 'new-chat', icon: SquarePen, keys: ['shift', 'cmd', 'o'], tooltip: 'New chat' },
 	{ icon: Search, keys: ['cmd', 'k'], tooltip: 'Search' },
 	{
 		activeRouteId: '/mcp-servers',

tools/ui/src/lib/hooks/use-keyboard-shortcuts.svelte.ts

@@ -1,6 +1,5 @@
-import { goto } from '$app/navigation';
-import { ROUTES } from '$lib/constants';
 import { KeyboardKey } from '$lib/enums';
+import { conversationsStore } from '$lib/stores';
 
 interface KeyboardShortcutsCallbacks {
 	activateSearchMode?: () => void;
@@ -34,7 +33,7 @@ export function useKeyboardShortcuts(callbacks: KeyboardShortcutsCallbacks) {
 		) {
 			event.preventDefault();
 
-			goto(ROUTES.NEW_CHAT);
+			conversationsStore.openNewChatTab();
 		}
 
 		if (event.shiftKey && isCmdOrCtrl && event.key === KeyboardKey.E_UPPER) {

tools/ui/src/lib/types/navigation.d.ts

@@ -7,6 +7,8 @@ export interface DesktopIconStripItem {
 	icon: Component;
 	tooltip: string;
 	route?: string;
+	/** Custom action handled by the sidebar, e.g. opening a new-chat tab */
+	action?: 'new-chat';
 	activeRouteId?: string;
 	activeRoutePrefix?: string;
 	activeUrlIncludes?: string;

tools/ui/src/routes/+layout.svelte

@@ -96,7 +96,7 @@
 		if (targetIdx >= 0 && targetIdx < allConvs.length) {
 			goto(RouterService.chat(allConvs[targetIdx].id));
 		} else {
-			goto(ROUTES.NEW_CHAT);
+			conversationsStore.openNewChatTab();
 		}
 	}
 

tools/ui/src/routes/search/+page.svelte

@@ -3,7 +3,6 @@
 	import { goto } from '$app/navigation';
 	import { page } from '$app/state';
 	import { SearchInput, SidebarNavigationSearchResults } from '$lib/components/app';
-	import { ROUTES } from '$lib/constants';
 	import { RouterService } from '$lib/services/router.service';
 	import { chatStore, conversationsStore, deviceStore } from '$lib/stores';
 
@@ -21,10 +20,10 @@
 	});
 
 	// Search page is intended for mobile; on desktop the sidebar already exposes
-	// in-place search, so bounce back to a chat.
+	// in-place search, so bounce back to a new-chat tab.
 	$effect(() => {
 		if (browser && !deviceStore.isMobile) {
-			goto(ROUTES.NEW_CHAT, { replaceState: true });
+			conversationsStore.openNewChatTab();
 		}
 	});
 
@@ -66,7 +65,7 @@
 		if (history.length > 1) {
 			history.back();
 		} else {
-			goto(ROUTES.NEW_CHAT);
+			conversationsStore.openNewChatTab();
 		}
 	}
 </script>