docs(architecture): update to v1.3 — all Phase 8 gaps closed

Adds solitaire_wasm crate (§2/§3), replay API endpoints (§9), web
replay player routes, SyncProvider 7 optional methods, ThemePlugin +
SyncSetupPlugin in plugin table (§5), Settings new fields (§8), and
DB migration 002 replays table (§7). Also fixes missing [0.23.0]
section header in CHANGELOG.md.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -6,6 +6,10 @@ project follows [Semantic Versioning](https://semver.org/).
 
 ## [Unreleased]
 
+---
+
+## [0.23.0] — 2026-05-12
+
 Phase 8 sync UI: the self-hosted-server connection flow is now fully
 playable end-to-end. Players can open a Connect modal from Settings,
 enter a server URL + credentials, log in or register, and see the