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).

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 d0a1.es
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.