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/bits/utilities/arrow/arrow.svelte

@@ -0,0 +1,30 @@
+<script lang="ts">
+	import { mergeProps } from "svelte-toolbelt";
+	import type { ArrowProps } from "./types.js";
+	import { useId } from "../../../internal/use-id.js";
+
+	let {
+		id = useId(),
+		children,
+		child,
+		width = 10,
+		height = 5,
+		...restProps
+	}: ArrowProps = $props();
+
+	const mergedProps = $derived(mergeProps(restProps, { id }));
+</script>
+
+{#if child}
+	{@render child({ props: mergedProps })}
+{:else}
+	<span {...mergedProps}>
+		{#if children}
+			{@render children?.()}
+		{:else}
+			<svg {width} {height} viewBox="0 0 30 10" preserveAspectRatio="none" data-arrow="">
+				<polygon points="0,0 30,0 15,10" fill="currentColor" />
+			</svg>
+		{/if}
+	</span>
+{/if}

web/node_modules/bits-ui/dist/bits/utilities/arrow/arrow.svelte.d.ts

@@ -0,0 +1,4 @@
+import type { ArrowProps } from "./types.js";
+declare const Arrow: import("svelte").Component<ArrowProps, {}, "">;
+type Arrow = ReturnType<typeof Arrow>;
+export default Arrow;

web/node_modules/bits-ui/dist/bits/utilities/arrow/index.d.ts

@@ -0,0 +1,2 @@
+export { default as Arrow } from "./arrow.svelte";
+export type { ArrowProps } from "./types.js";

web/node_modules/bits-ui/dist/bits/utilities/arrow/index.js

@@ -0,0 +1 @@
+export { default as Arrow } from "./arrow.svelte";

web/node_modules/bits-ui/dist/bits/utilities/arrow/types.d.ts

@@ -0,0 +1,17 @@
+import type { WithChild } from "../../../internal/types.js";
+import type { BitsPrimitiveSpanAttributes } from "../../../shared/attributes.js";
+export type ArrowPropsWithoutHTML = WithChild<{
+    /**
+     * The width of the arrow in pixels.
+     *
+     * @defaultValue 10
+     */
+    width?: number;
+    /**
+     * The height of the arrow in pixels.
+     *
+     * @defaultValue 5
+     */
+    height?: number;
+}>;
+export type ArrowProps = ArrowPropsWithoutHTML & BitsPrimitiveSpanAttributes;

web/node_modules/bits-ui/dist/bits/utilities/arrow/types.js

@@ -0,0 +1 @@
+export {};