feat(landing): rework — es default, 2-step join, roster + account polish

- Default language Spanish at root /, English moves to /en/ (eu unchanged):
  getStaticPaths {lang:undefined}->es + LANG_*_PATH maps swapped in ui.ts.
- Section order: hero -> join -> status -> members -> mods -> features.
- Join flow 3 -> 2 steps (drop the Connect/IP step; launcher handles the
  address). Remove the hero IP CopyChip. Header CTA renamed Play/Jugar/Jolastu
  and gains Register + Login links on all four pages.
- Account page: hide the whole login block once authenticated (not just the
  form), add an avatar Refresh button (cache-busted NMSR re-fetch), flatten the
  avatar (no bevel). New i18n key account.refresh.
- Register page: new REGISTRATION_SHOW_INVITE env (default false/hidden) toggles
  the invite-code field independently of the REGISTRATION_MODE backend gate.
- Members roster: drop the `admin` account, render full-body via a new
  ROSTER_AVATAR_MODE (default fullbodyiso); portrait tiles.
- Style: flatten emboss on feature icons (.picon) + player tiles (.roster-tile).
  PixelIcon gains optional image support (/icons/<name>.png|svg).
- Favicon now /favicon.png (committed) on all pages.
- Docs: plan/09-landing.md Assets section (logo/favicon/features-icons drop
  points) + default-language note; .env.example documents the two new vars.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

landing/src/components/PixelIcon.astro

@@ -1,10 +1,13 @@
 ---
-// 7x7 feature glyphs — styled by .picon in main.css.
+// Feature icon. Default: a 7x7 procedural glyph (styled by .picon in main.css).
+// Optional: pass `img` (an absolute path like "/icons/foo.png|svg" under
+// landing/public/) to render a custom image instead of a glyph.
 interface Props {
   glyph: "shield" | "diamond" | "orb" | "heart";
   gold?: boolean;
+  img?: string; // custom icon path in /public/icons/ — overrides the glyph
 }
-const { glyph, gold = false } = Astro.props;
+const { glyph, gold = false, img } = Astro.props;
 
 const GLYPHS: Record<Props["glyph"], string[]> = {
   shield: ["0111110", "1111111", "1111111", "1111111", "0111110", "0011100", "0001000"],
@@ -15,6 +18,10 @@ const GLYPHS: Record<Props["glyph"], string[]> = {
 const cells = GLYPHS[glyph].join("").split("");
 const onClass = gold ? "go" : "on";
 ---
-<div class="picon" aria-hidden="true">
-  {cells.map((c) => <i class={c === "1" ? onClass : undefined} />)}
-</div>
+{img ? (
+  <img class="picon-img" src={img} alt="" aria-hidden="true" width="52" height="52" />
+) : (
+  <div class="picon" aria-hidden="true">
+    {cells.map((c) => <i class={c === "1" ? onClass : undefined} />)}
+  </div>
+)}