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.

docker-compose.yml

@@ -0,0 +1,20 @@
+# oikos-web deploy stack — the control-room SPA container.
+#
+# Publishes the same host port the oikos stack's `web` service used
+# (8091:80); the outer production Caddy (caddy-conf repo, LXC 121) targets
+# this published port, so no shared Docker network with the oikos stack is
+# needed. Images are version-tagged by scripts/deploy.sh
+# (oikos-web:v$VERSION); `latest` is only a manual-build fallback.
+
+services:
+  web:
+    image: oikos-web:${OIKOS_VERSION:-latest}
+    build:
+      context: .
+      dockerfile: compose/Dockerfile
+    restart: unless-stopped
+    ports:
+      - "8091:80"
+    stop_signal: SIGTERM
+    mem_limit: 64m
+    cpus: 0.25