se abre en nueva pestaña (#162)

Fix: #159

Añadidos dos avisos para sr (screen reader) de `se abre en nueva
pestaña`

Author: ctrl-alt-d

src/components/home/SectionCallForProposals.astro

@@ -1,5 +1,6 @@
 ---
 import { texts } from '../../i18n/home'
+import { menuTexts } from '../../i18n/menu'
 import SectionTitle from '../SectionTitle.astro'
 import Button from '../Button.astro'
 
@@ -9,6 +10,7 @@ interface Props {
 
 const { lang } = Astro.props
 const t = texts[lang as keyof typeof texts]
+const menuT = menuTexts[lang as keyof typeof menuTexts]
 ---
 
 <div class="flex flex-col items-center gap-6">
@@ -28,6 +30,7 @@ const t = texts[lang as keyof typeof texts]
         href="https://pretalx.com/pycones-2026/cfp"
         target="_blank"
         rel="noopener noreferrer"
+        aria-label={`${t['cfp.button']} ${menuT.new_tab}`}
       >
         {t['cfp.button']}
       </Button>

src/components/home/sponsors/SponsorsGroup.astro

@@ -1,6 +1,7 @@
 ---
 import type { ISponsor } from '../../../types/sponsors'
 import { texts } from '../../../i18n/home'
+import { menuTexts } from '../../../i18n/menu'
 
 interface Props {
   lang: string
@@ -12,6 +13,7 @@ interface Props {
 
 const { title, sponsors, lang, tierColor, size } = Astro.props
 const t = texts[lang as keyof typeof texts]
+const menuT = menuTexts[lang as keyof typeof menuTexts]
 ---
 
 {
@@ -28,6 +30,7 @@ const t = texts[lang as keyof typeof texts]
             href={sponsor.website}
             target="_blank"
             rel="noopener noreferrer"
+            aria-label={`${t['sponsors.altlogo'].replace('{name}', sponsor.name)} ${menuT.new_tab}`}
             class="group relative flex items-center justify-center rounded-xl bg-white/[0.03] border border-white/[0.06] backdrop-blur-sm p-5 transition-all duration-300 hover:bg-white/[0.08] hover:border-white/[0.15] hover:scale-[1.03] hover:shadow-lg hover:shadow-black/20"
           >
             <img