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/runed/dist/utilities/is-idle/is-idle.svelte.js

@@ -0,0 +1,63 @@
+import { extract } from "../extract/index.js";
+import { useDebounce } from "../use-debounce/index.js";
+import { useEventListener } from "../use-event-listener/use-event-listener.svelte.js";
+import { defaultWindow, } from "../../internal/configurable-globals.js";
+const DEFAULT_EVENTS = [
+    "keypress",
+    "mousemove",
+    "touchmove",
+    "click",
+    "scroll",
+];
+const DEFAULT_OPTIONS = {
+    events: DEFAULT_EVENTS,
+    initialState: false,
+    timeout: 60000,
+};
+/**
+ * Tracks whether the user is being inactive.
+ * @see {@link https://runed.dev/docs/utilities/is-idle}
+ */
+export class IsIdle {
+    #current = $state(false);
+    #lastActive = $state(Date.now());
+    constructor(_options) {
+        const opts = {
+            ...DEFAULT_OPTIONS,
+            ..._options,
+        };
+        const window = opts.window ?? defaultWindow;
+        const document = opts.document ?? window?.document;
+        const timeout = $derived(extract(opts.timeout));
+        const events = $derived(extract(opts.events));
+        const detectVisibilityChanges = $derived(extract(opts.detectVisibilityChanges));
+        this.#current = opts.initialState;
+        const debouncedReset = useDebounce(() => {
+            this.#current = true;
+        }, () => timeout);
+        debouncedReset();
+        const handleActivity = () => {
+            this.#current = false;
+            this.#lastActive = Date.now();
+            debouncedReset();
+        };
+        useEventListener(() => window, () => events, () => {
+            handleActivity();
+        }, { passive: true });
+        $effect(() => {
+            if (!detectVisibilityChanges || !document)
+                return;
+            useEventListener(document, ["visibilitychange"], () => {
+                if (document.hidden)
+                    return;
+                handleActivity();
+            });
+        });
+    }
+    get lastActive() {
+        return this.#lastActive;
+    }
+    get current() {
+        return this.#current;
+    }
+}