feat(design): apply Monolith Editorial design system to all Fase 1 screens

- Remove all 1px border separators (sidebar border-r, page header border-b,
  section border-t, member list divide-y, invite card border). Separation is
  now achieved via background color shifts and whitespace per the "No-Line" rule.
- Fix sidebar: bg-surface-raised vs bg-background creates tonal separation.
- Correct dark background to #020617 (slate-950) per spec.
- Add surface-container-low, text-primary/secondary/muted, destructive tokens.
- Fix CSS variable color space: all tokens are RGB triplets; switch Tailwind
  config and app.css from hsl() to rgb() to prevent yellow/warm color bleed.
- Replace emoji nav icons with Lucide icons at 16px / 1.5 stroke-width.
- Apply Masthead typography (uppercase Label-MD + Title-LG) to all page headers
  and section labels across lists, tasks, notes, search, settings, manage.
- Destructive action (sign out) uses bg-destructive per spec.
- Add `just serve` command: builds and runs the prod Node server at :3000
  against the dev Docker stack for production build testing.
- Add nav_collective i18n key (en + es).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/web/src/routes/(app)/collective/manage/+page.svelte

@@ -136,25 +136,32 @@
 	}
 </script>
 
-<div class="flex-1 overflow-y-auto p-6">
-	<h1 class="mb-6 text-xl font-bold text-slate-900 dark:text-slate-50">
+<div class="flex flex-1 flex-col overflow-hidden">
+<div class="flex-1 overflow-y-auto">
+<div class="px-8 pb-4 pt-8">
+	<p class="mb-1 text-[13px] font-semibold uppercase tracking-[0.05em] text-text-secondary">
+		{m.nav_collective()}
+	</p>
+	<h1 class="text-[20px] font-semibold tracking-[-0.01em] text-slate-900 dark:text-slate-50">
 		{m.manage_title()}
 	</h1>
+</div>
+<div class="px-8 py-6">
 
 	{#if error}
 		<p class="mb-4 text-sm text-red-600">{error}</p>
 	{/if}
 
-	<!-- Members list -->
+	<!-- Members list — no dividers, vertical padding creates separation -->
 	<section class="mb-8">
-		<h2 class="mb-3 text-sm font-semibold uppercase tracking-wide text-text-secondary">
+		<h2 class="mb-4 text-[13px] font-semibold uppercase tracking-[0.05em] text-text-secondary">
 			{m.manage_members()}
 		</h2>
 
 		{#if loading}
 			<p class="text-sm text-text-secondary">{m.loading()}</p>
 		{:else}
-			<ul class="divide-y divide-slate-100 dark:divide-slate-700">
+			<ul>
 				{#each members as member}
 					<li class="flex items-center gap-3 py-3">
 						<Avatar
@@ -202,10 +209,10 @@
 		{/if}
 	</section>
 
-	<!-- Invite link generator (admins only) -->
+	<!-- Invite link generator — background shift instead of border -->
 	{#if isAdmin}
-		<section class="rounded-lg border border-slate-200 p-4 dark:border-slate-700">
-			<h2 class="mb-3 text-sm font-semibold text-slate-900 dark:text-slate-50">
+		<section class="rounded-lg bg-surface-container-low p-4 dark:bg-surface-raised">
+			<h2 class="mb-3 text-[13px] font-semibold uppercase tracking-[0.05em] text-text-secondary">
 				{m.manage_invite_title()}
 			</h2>
 
@@ -232,8 +239,7 @@
 			</button>
 
 			{#if generatedLink}
-				<div class="flex items-center gap-2 rounded-lg border border-slate-200 bg-slate-50 p-2
-					dark:border-slate-700 dark:bg-slate-800">
+				<div class="flex items-center gap-2 rounded-lg bg-surface p-2 dark:bg-surface-raised">
 					<code class="min-w-0 flex-1 truncate text-xs text-slate-600 dark:text-slate-400">
 						{generatedLink}
 					</code>
@@ -250,3 +256,5 @@
 		</section>
 	{/if}
 </div>
+</div>
+</div>