fix: align quickstart with d0a1.es ecosystem and current reality

Hardening pass over the quickstart repo to make it match the actual
d0a1.es stack and remove long-standing drift.

- README: align with 8 GB RAM reality across all sections, add
  explicit security warning on WEBUI_AUTH=false, remove dead link
  to d0a1.es/vps, drop stack services not part of d0a1.es
  (n8n, WordPress, Qdrant). Re-point the d0a1 section to the
  services that actually run at git/mail/app.d0a1.es.
- docker-compose: move all tunables (ports, default model, auth,
  secret key, keep-alive) to .env with sensible defaults. Add
  commented GPU passthrough block for NVIDIA hosts.
- deploy.sh: pre-flight checks (docker, compose, daemon),
  copy .env.example on first run, auto-detect system RAM on
  Linux and macOS and warn on sub-8 GB hosts.
- Add .env.example documenting every variable and required RAM
  per model.
- Add MIT LICENSE (was promised in README but missing).
- Add .gitignore (local .env, editor cruft, OS junk).
- .gitattributes: use a single rule (text=auto eol=lf) to cover
  every text file, not just *.sh - fixes CRLF warnings on new
  text files on Windows checkouts.

Refs: d0a1/quickstart rename (companion: new repo at
git.d0a1.es/d0a1/quickstart).

.gitignore

@@ -0,0 +1,17 @@
+# Configuracion local (no commitear - contiene secretos)
+.env
+
+# Volumenes Docker (gestion por docker compose)
+# Si necesitas persistencia, los volumenes named se crean en docker volume ls.
+
+# OS / editor cruft
+.DS_Store
+Thumbs.db
+*.swp
+*.swo
+*~
+.vscode/
+.idea/
+
+# Logs
+*.log