docs(readme): correct fork-sync version (v4.12.3) and logo path

Two stale facts in README.md: it said "Forked from Cinny v4.12.1" (we've since
synced through v4.12.3) and referenced the logo as lotus_chat.png (the file is
public/res/Lotus.png). CONTRIBUTING.md is intentionally left as upstream
Cinny's and is not modified.

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

LOTUS_BUGS.md

@@ -68,7 +68,7 @@ Implemented and gate-green; confirm each per `LOTUS_TESTING.md`, then delete the
 - **Hardcoded CDN URL** should move to an env var (the decoration CDN is now single-sourced in `avatarDecorations.ts`, but the literal is still in-repo).
 - **`patch-folds.mjs` edits `node_modules` directly** — consider `patch-package`.
 - **Infra docs:** `contrib/nginx` lacks security headers (HSTS/CSP) + uses rewrites over `try_files`; `contrib/caddy` has a placeholder path. CI/CD (`prod-deploy.yml`): sequential deploy, aggressive 1-min Netlify timeout, `package-manager-cache: false`.
-- **README / CONTRIBUTING:** stale upstream bug-tracker/donations/CLA links; README↔CONTRIBUTING misalignment.
+- **README:** keep the fork-sync version + logo path current. (`CONTRIBUTING.md` is intentionally left as upstream Cinny's — not a Lotus concern.)
 - **Architecture notes (low priority):** deep `features/` + `hooks/` nesting, many small coupled hooks, possible dead CSS/components, `SpacingVariant` / `DropTarget` recipe simplification.
 - **Git workflow (forward-looking):** keep commits scoped — past monolithic "fix all bugs" commits and inconsistent prefixes hurt `git bisect`.