feat(dashboard): add MeDto, AdminDto, apiKeys + role/password helpers

Extends api.ts with the Phase 3.5 wire types (InstanceRole, Scope,
MeDto, AdminDto, ApiKeyDto, MintApiKey*) and the matching apiKeys
namespace. AdminUser in auth.ts now carries instance_role and email,
so layout/store consumers see the role without a separate fetch.

Adds two tiny lib helpers used by the upcoming profile/users pages:
RoleChip.svelte for the colored owner/admin/member pill, and
password-gen.ts for crypto.getRandomValues-backed temporary
passwords used in user-invite + reset-password reveals.

AdminUserRecord stays as a deprecated alias until /admins is
retired in a follow-up commit.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

dashboard/src/lib/RoleChip.svelte

@@ -0,0 +1,45 @@
+<script lang="ts">
+	import type { InstanceRole } from '$lib/auth';
+
+	interface Props {
+		role: InstanceRole;
+		size?: 'sm' | 'md';
+	}
+
+	let { role, size = 'md' }: Props = $props();
+</script>
+
+<span class="chip chip-{role}" class:sm={size === 'sm'}>{role}</span>
+
+<style>
+	.chip {
+		display: inline-flex;
+		align-items: center;
+		padding: 0.15rem 0.55rem;
+		border-radius: 999px;
+		font-size: 0.7rem;
+		font-weight: 600;
+		text-transform: uppercase;
+		letter-spacing: 0.04em;
+		border: 1px solid transparent;
+	}
+	.chip.sm {
+		font-size: 0.625rem;
+		padding: 0.1rem 0.45rem;
+	}
+	.chip-owner {
+		background: #78350f;
+		color: #fbbf24;
+		border-color: #b45309;
+	}
+	.chip-admin {
+		background: #164e63;
+		color: #67e8f9;
+		border-color: #0e7490;
+	}
+	.chip-member {
+		background: #1e293b;
+		color: #cbd5e1;
+		border-color: #334155;
+	}
+</style>