release(v1.0.0): cut v1.0.0 release from Fase 17–20 cycle

- Bump package.json from 1.0.0-rc.0 to 1.0.0.
- Move all [Unreleased] entries (Fases 18/19/20) into a new
  [v1.0.0] — 2026-05-19 section. Add a corresponding Fase 17 entry
  (versioning + CHANGELOG tooling itself) that wasn't in [Unreleased]
  because the linter wasn't wired during 17's own work.
- Tag v1.0.0 (local only; not pushed) immediately after this commit.

Closes the v1.0 cycle:
- Fase 17 — versioning + CHANGELOG + about modal + deploy tag check.
- Fase 18 — required list title + #N auto-numbering + default + catalog.
- Fase 19 — emoji picker with food + animals categories.
- Fase 20 — Euskera locale (machine-translated seed pending review).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

package.json

@@ -1,7 +1,7 @@
 {
   "name": "colectivo",
   "private": true,
-  "version": "1.0.0-rc.0",
+  "version": "1.0.0",
   "scripts": {
     "build": "turbo run build",
     "dev": "turbo run dev --parallel",