oikos-web: extract the client stack from dtoro/oikos

Phase 1 of the hexagonal-architecture plan (dtoro/oikos
plans/2026-08-15-hexagonal-architecture.md). Moves the delivery stack
for the control-room UI into its own repo with its own pipeline:

- web/ — Svelte 5 SPA, verbatim (vendor/ included)
- desktop/ — Wails v3 wrapper, updateURL repointed to
  dtoro/oikos-web releases
- compose/ — Dockerfile + Caddyfile, verbatim (the /wails/* 404 and
  asset no-fallback quirks are load-bearing)
- docker-compose.yml — single web service, same 8091:80 publish,
  mem/cpu limits, and restart policy as the oikos stack's web service
- scripts/deploy.sh — mirrors oikos deploy essentials: CI-green gate,
  TOCTOU guard, version-tagged oikos-web:v$VERSION, prune to 3
- cmd/webhook + scripts/install-webhook.sh — standalone push-to-deploy
  receiver on :9798 (env-only secrets, no Infisical dependency)
- CI: the web job from oikos's ci.yml + the desktop build/release
  workflow, path-adjusted

Own VERSION (0.33.0) with the same bump-on-main rule; starts above
oikos's 0.32.x so the desktop updater sees an upgrade.

web/public/mascot/LICENSE.txt

@@ -0,0 +1,5 @@
+
+CC0 1.0 Universal (CC0 1.0) Public Domain Dedication 
+
+The person who associated a work with this deed has dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
+You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission.