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/bits-ui/dist/internal/date-time/announcer.js

@@ -0,0 +1,82 @@
+import { srOnlyStylesString } from "svelte-toolbelt";
+import { isBrowser, isHTMLElement } from "../is.js";
+/**
+ * Creates or gets an announcer element which is used to announce messages to screen readers.
+ * Within the date components, we use this to announce when the values of the individual segments
+ * change, as without it we get inconsistent behavior across screen readers.
+ */
+function initAnnouncer(doc) {
+    if (!isBrowser || !doc)
+        return null;
+    let el = doc.querySelector("[data-bits-announcer]");
+    /**
+     * Creates a log element for assertive or polite announcements.
+     */
+    const createLog = (kind) => {
+        const log = doc.createElement("div");
+        log.role = "log";
+        log.ariaLive = kind;
+        log.setAttribute("aria-relevant", "additions");
+        return log;
+    };
+    if (!isHTMLElement(el)) {
+        const div = doc.createElement("div");
+        div.style.cssText = srOnlyStylesString;
+        div.setAttribute("data-bits-announcer", "");
+        div.appendChild(createLog("assertive"));
+        div.appendChild(createLog("polite"));
+        el = div;
+        doc.body.insertBefore(el, doc.body.firstChild);
+    }
+    /**
+     * Retrieves the log element for assertive or polite announcements.
+     */
+    const getLog = (kind) => {
+        if (!isHTMLElement(el))
+            return null;
+        const log = el.querySelector(`[aria-live="${kind}"]`);
+        if (!isHTMLElement(log))
+            return null;
+        return log;
+    };
+    return {
+        getLog,
+    };
+}
+/**
+ * Creates an announcer object that can be used to make `aria-live` announcements to screen readers.
+ */
+export function getAnnouncer(doc) {
+    const announcer = initAnnouncer(doc);
+    /**
+     * Announces a message to screen readers using the specified kind of announcement.
+     */
+    function announce(value, kind = "assertive", timeout = 7500) {
+        if (!announcer || !isBrowser || !doc)
+            return;
+        const log = announcer.getLog(kind);
+        const content = doc.createElement("div");
+        if (typeof value === "number") {
+            value = value.toString();
+        }
+        else if (value === null) {
+            value = "Empty";
+        }
+        else {
+            value = value.trim();
+        }
+        content.innerText = value;
+        if (kind === "assertive") {
+            log?.replaceChildren(content);
+        }
+        else {
+            log?.appendChild(content);
+        }
+        return setTimeout(() => {
+            content.remove();
+        }, timeout);
+    }
+    return {
+        announce,
+    };
+}