docs: add HANDOFF.md (full project state) + point CLAUDE.md at it

Single source of truth for any agent/session continuing the project: run
instructions (dev + Docker stack), architecture, the client<->server
gamification sync rule, full feature status, CI/CD + Nexus HTTP-mirror cert
workaround, gotchas, and the TODO list.

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

CLAUDE.md

@@ -1 +1,18 @@
 @AGENTS.md
+
+# Barg-e Vasat (Hokm) — start here
+
+**Read `HANDOFF.md` first** — it is the single source of truth for this project:
+what it is, how to run (dev + Docker stack), the architecture, the
+client↔server gamification sync rule, feature status, CI/CD + mirror cert
+workaround, and the TODO list.
+
+Quick facts:
+- Next.js 16 static-export app at root; .NET 10 SignalR backend in `server/`.
+- Git remote `origin` = Gitea (`soroushdes/HokmPlay`, branch `main`); push triggers CI/CD.
+- i18n: add every string to BOTH `fa` and `en` in `src/lib/i18n.tsx`.
+- Gamification lives in `src/lib/online/gamification.ts` (client) AND
+  `server/src/Hokm.Server/Profiles/Gamification.cs` (server) — keep them in sync;
+  the server is authoritative in live mode.
+- Verify before committing: `npx tsc --noEmit` · `npx tsx scripts/sim.ts` ·
+  `dotnet build server/Hokm.slnx -c Release` · `npm run build`.