feat(web-player): rebuild Inicio and Buscar to the design handoff

Applies the handoff's layout and image shapes while keeping the current
Musify design system (Inter, colors, tokens) — no font or palette swap.

Inicio now stacks distinct shelves instead of repeated square grids:
recently played rows, a rail of recently listened albums with an "Álbum"
badge, a "Hecho para ti" bento of mixes, a rail of playlists with a
trailing dashed "Ver todas" tile, tall "Canciones nuevas" posters with a
"Nuevo" badge, a rail of circular top-artist avatars, and a recommended
rail. Buscar splits into Álbumes (square cards + badge), Usuarios (a
circular-avatar directory) and a flat Canciones list.

Top artists and the search user directory are filler data until the
backend exposes them. New shared pieces: Rail, CoverBadge, ArtistAvatar,
MixBentoTile. The orphaned TrackTile and MixCard are removed.

web-player/src/routes/(app)/explore/+page.server.ts

@@ -13,6 +13,7 @@ import {
 	SEARCH_MIN_LENGTH,
 	YOUTUBE_FILLER_LIMIT
 } from '$lib/config';
+import { searchUsers } from '$lib/server/userDirectory';
 
 export const load: PageServerLoad = async ({ url, locals, fetch }) => {
 	const query = url.searchParams.get('q')?.trim() ?? '';
@@ -62,6 +63,7 @@ export const load: PageServerLoad = async ({ url, locals, fetch }) => {
 		youtubeAlbums: youtubeAlbumsRes?.data?.items ?? [],
 		ytResults: searchRes?.data ?? null,
 		ytError: Boolean(searchRes?.error),
+		users: searchUsers(query),
 		youtubeFiller: query
 			? Promise.resolve(null)
 			: fetchYoutubeFiller(api, locals.accessToken, YOUTUBE_FILLER_LIMIT),