Update sponsorship package availability: Platinum → 0, Gold → 1 (#218)

Reflects current sponsorship availability: Platinum is sold out (0),
Gold has 1 slot remaining.

## Changes
- `src/i18n/sponsors/en.ts`, `es.ts`, `ca.ts`: updated `limit` field in
the `tiers` array
  - `Platinum`: `2 avail.` → `0 avail.` / `2 disp.` → `0 disp.`
  - `Gold`: `0 avail.` → `1 avail.` / `0 disp.` → `1 disp.`

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

Author: Copilot

src/i18n/sponsors/ca.ts

@@ -228,7 +228,7 @@ export const ca = {
         emoji: '🌟',
         iconName: 'gold',
         price: 'Preu 6.000€',
-        limit: '0 disp.',
+        limit: '1 disp.',
         bg: 'rgba(234, 179, 8, 0.1)',
       },
       {
@@ -237,7 +237,7 @@ export const ca = {
         emoji: '🏆',
         iconName: 'platinum',
         price: 'Preu 8.000€',
-        limit: '2 disp.',
+        limit: '0 disp.',
         bg: 'rgba(34, 197, 94, 0.1)',
       },
       {

src/i18n/sponsors/en.ts

@@ -232,7 +232,7 @@ export const en = {
         emoji: '🌟',
         iconName: 'gold',
         price: 'Price €6,000',
-        limit: '0 avail.',
+        limit: '1 avail.',
         bg: 'rgba(234, 179, 8, 0.1)',
       },
       {
@@ -241,7 +241,7 @@ export const en = {
         emoji: '🏆',
         iconName: 'platinum',
         price: 'Price €8,000',
-        limit: '2 avail.',
+        limit: '0 avail.',
         bg: 'rgba(34, 197, 94, 0.1)',
       },
       {

src/i18n/sponsors/es.ts

@@ -248,7 +248,7 @@ export const es = {
         emoji: '🌟',
         iconName: 'gold',
         price: 'Precio 6.000€',
-        limit: '0 disp.',
+        limit: '1 disp.',
         bg: 'rgba(234, 179, 8, 0.1)',
       },
       {
@@ -257,7 +257,7 @@ export const es = {
         emoji: '🏆',
         iconName: 'platinum',
         price: 'Precio 8.000€',
-        limit: '2 disp.',
+        limit: '0 disp.',
         bg: 'rgba(34, 197, 94, 0.1)',
       },
       {