feat: Phase 1 — extract the client (web SPA + desktop) to dtoro/oikos-web

Problem: the hexagonal refactor churns the backend tree for nine more
phases; the UI delivery stack (web/ SPA, cmd/desktop Wails wrapper,
compose/web image) must move to its own repo first so doc/layout
rewrites land once on a backend-only tree.

Change:
- New repo git.hubris.network/dtoro/oikos-web (v0.33.0): web/, desktop/
  (updateURL repointed to oikos-web releases), compose/, own CI (web +
  desktop jobs), own deploy script (CI-green gate, TOCTOU guard,
  version-tagged images, prune-to-3), own webhook receiver on :9798 +
  launchd unit, own compose project publishing the same 8091:80.
- Cutover executed on mac-mini in order: oikos stack's web service
  stopped+removed, oikos-web project brought up on 8091; outer Caddy
  untouched (targets the published port) — serving + Authentik flow +
  /wails 404 quirk verified post-cutover.
- Stripped from oikos: web/, cmd/desktop/, compose/web/, desktop CI
  workflow, ci.yml web job, Makefile ui/desktop/desktop-package/install
  targets, the compose web service, oikos-web from deploy.sh's fallback
  prune list; wails + go-keyring dropped from go.mod, vendor synced.
- README / CONTRIBUTING / AGENTS.md / .agents dev+operations docs now
  point at the new repo; mbse + mascot design docs carry a path note.

Risk: production SPA serving depends on the new pipeline now; rollback
is versioned-image re-up of the old web service from a pre-split
checkout (port 8091). Desktop builds installed before the split still
check dtoro/oikos releases — one manual reinstall, noted in the
oikos-web release notes.

Verification: go vet, make test (race), make generate-check, golangci
(no new findings; baseline down 400→365); post-cutover curls —
localhost:8091 200, /wails/runtime.js 404, outer Caddy 302 Authentik.

web/node_modules/svelte-toolbelt/dist/utils/dom-context.svelte.js

@@ -0,0 +1,50 @@
+import { boxWith } from "../box/box-extras.svelte.js";
+import { getActiveElement, getDocument } from "./dom.js";
+export class DOMContext {
+    element;
+    root = $derived.by(() => {
+        if (!this.element.current)
+            return document;
+        const rootNode = this.element.current.getRootNode() ?? document;
+        return rootNode;
+    });
+    constructor(element) {
+        if (typeof element === "function") {
+            this.element = boxWith(element);
+        }
+        else {
+            this.element = element;
+        }
+    }
+    getDocument = () => {
+        return getDocument(this.root);
+    };
+    getWindow = () => {
+        return this.getDocument().defaultView ?? window;
+    };
+    getActiveElement = () => {
+        return getActiveElement(this.root);
+    };
+    isActiveElement = (node) => {
+        return node === this.getActiveElement();
+    };
+    getElementById(id) {
+        return this.root.getElementById(id);
+    }
+    querySelector = (selector) => {
+        if (!this.root)
+            return null;
+        return this.root.querySelector(selector);
+    };
+    querySelectorAll = (selector) => {
+        if (!this.root)
+            return [];
+        return this.root.querySelectorAll(selector);
+    };
+    setTimeout = (callback, delay) => {
+        return this.getWindow().setTimeout(callback, delay);
+    };
+    clearTimeout = (timeoutId) => {
+        return this.getWindow().clearTimeout(timeoutId);
+    };
+}