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.

.gitea/workflows/ci.yml

@@ -0,0 +1,36 @@
+# oikos-web CI (Gitea Actions) — SPA pipeline, mirrors the web job this
+# repo inherited from dtoro/oikos.
+name: ci
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  web:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: web
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '22'
+          cache: npm
+          cache-dependency-path: web/package-lock.json
+      - run: npm ci
+      - name: svelte-check (advisory — baseline not yet clean)
+        run: npm run check
+        continue-on-error: true
+      - name: eslint (advisory — baseline not yet clean)
+        run: npm run lint
+        continue-on-error: true
+      - name: prettier format check (advisory — baseline not yet clean)
+        run: npm run format:check
+        continue-on-error: true
+      - name: test
+        run: npm run test
+      - name: build
+        run: npm run build