Fix team name blink on navigation by lifting teams into a singleton store

Teams list was fetched on every Sidebar mount (each page navigation),
causing a flash from '…' to the real name on every tab switch. Move teams
into a module-level reactive store (teams.svelte.ts) that fetches once per
session and is shared between Sidebar and the team page.

frontend/src/lib/components/Sidebar.svelte

@@ -3,7 +3,8 @@
 	import { onMount } from 'svelte';
 	import { Popover } from 'bits-ui';
 	import { auth } from '$lib/auth.svelte';
-	import { listTeams, createTeam, switchTeam, type TeamWithRole } from '$lib/api/team';
+	import { teams as teamsStore } from '$lib/teams.svelte';
+	import { createTeam, switchTeam } from '$lib/api/team';
 	import {
 		IconMonitor,
 		IconBox,
@@ -25,9 +26,7 @@
 
 	let teamPopoverOpen = $state(false);
 
-	// Real teams from API
+	let currentTeamName = $derived(teamsStore.list.find((t) => t.id === auth.teamId)?.name ?? '');
-	let teams = $state<TeamWithRole[]>([]);
-	let currentTeamName = $derived(teams.find((t) => t.id === auth.teamId)?.name ?? '');
 	let userName = $derived(auth.email ?? '');
 
 	// Create team dialog
@@ -69,10 +68,7 @@
 	}
 
 	async function fetchTeams() {
-		const result = await listTeams();
+		await teamsStore.fetch();
-		if (result.ok) {
-			teams = result.data;
-		}
 	}
 
 	async function handleSwitchTeam(teamId: string) {
@@ -180,7 +176,7 @@
 					>
 						Teams
 					</div>
-					{#each teams as team (team.id)}
+					{#each teamsStore.list as team (team.id)}
 						<button
 							class="flex w-full items-center gap-2.5 rounded-[var(--radius-input)] px-2.5 py-2 text-ui transition-colors duration-150 hover:bg-[var(--color-bg-3)] {team.id ===
 							auth.teamId

frontend/src/lib/teams.svelte.ts

@@ -0,0 +1,31 @@
+import { listTeams, type TeamWithRole } from '$lib/api/team';
+
+function createTeamsStore() {
+	let teams = $state<TeamWithRole[]>([]);
+	let loaded = $state(false);
+
+	return {
+		get list() {
+			return teams;
+		},
+		get loaded() {
+			return loaded;
+		},
+		async fetch() {
+			if (loaded) return;
+			const result = await listTeams();
+			if (result.ok) {
+				teams = result.data;
+				loaded = true;
+			}
+		},
+		// Call after mutating teams (create/switch triggers a full reload, but
+		// adding a team locally avoids a flicker in the popover list).
+		set(newTeams: TeamWithRole[]) {
+			teams = newTeams;
+			loaded = true;
+		}
+	};
+}
+
+export const teams = createTeamsStore();

frontend/src/routes/dashboard/team/+page.svelte

@@ -17,9 +17,9 @@
 		searchUsers,
 		type TeamInfo,
 		type TeamMember,
-		type TeamWithRole,
 		type UserSearchResult
 	} from '$lib/api/team';
+	import { teams as teamsStore } from '$lib/teams.svelte';
 
 	let collapsed = $state(
 		typeof window !== 'undefined'
@@ -30,12 +30,11 @@
 	// Page data
 	let team = $state<TeamInfo | null>(null);
 	let members = $state<TeamMember[]>([]);
-	let allTeams = $state<TeamWithRole[]>([]);
 	let loading = $state(true);
 	let error = $state<string | null>(null);
 
 	// True when this is the user's only team — deleting/leaving would leave them teamless
-	let isLastTeam = $derived(allTeams.length <= 1);
+	let isLastTeam = $derived(teamsStore.list.length <= 1);
 
 	// Current user's role — derived from members list
 	let myRole = $derived(members.find((m) => m.user_id === auth.userId)?.role ?? 'member');
@@ -86,9 +85,9 @@
 			loading = false;
 			return;
 		}
-		const [teamResult, teamsResult] = await Promise.all([
+		const [teamResult] = await Promise.all([
 			getTeam(auth.teamId),
-			listTeams()
+			teamsStore.fetch()
 		]);
 		if (teamResult.ok) {
 			team = teamResult.data.team;
@@ -96,9 +95,6 @@
 		} else {
 			error = teamResult.error;
 		}
-		if (teamsResult.ok) {
-			allTeams = teamsResult.data;
-		}
 		loading = false;
 	}