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-splitpanes/dist/index.d.ts

@@ -0,0 +1,60 @@
+import type { Readable } from 'svelte/store';
+export { default as Splitpanes } from './Splitpanes.svelte';
+export { default as Pane } from './Pane.svelte';
+export type PaneInitFunction = (_key: any) => {
+    undefinedPaneInitSize: number;
+};
+export interface ClientCallbacks {
+    onSplitterDown: (_event: TouchEvent | MouseEvent) => void;
+    onSplitterClick: (_event: MouseEvent) => void;
+    onSplitterDblClick: (_event: MouseEvent) => void;
+    onPaneClick: (_event: MouseEvent) => void;
+    /** Report the manual given size was changed. */
+    reportGivenSizeChange: (_newGivenSize: number) => void;
+}
+export interface SplitContext {
+    /** Tells the key of the very first pane, or undefined if not recieved yet. */
+    veryFirstPaneKey: Readable<any>;
+    isHorizontal: Readable<boolean>;
+    showFirstSplitter: Readable<boolean>;
+    ssrRegisterPaneSize?: (size: number | null) => void;
+    onPaneInit: PaneInitFunction;
+    clientOnly?: {
+        onPaneAdd: (pane: IPane) => ClientCallbacks;
+        onPaneRemove: (key: any) => Promise<void>;
+    };
+}
+/**
+ * Pane sizing details on an event.
+ */
+export interface IPaneSizingEvent {
+    /**
+     * Minimum size in %.
+     */
+    min: number;
+    /**
+     * Maximum size in %.
+     */
+    max: number;
+    /**
+     * Pane size in %.
+     */
+    size: number;
+    /**
+     * Snap size in %.
+     */
+    snap: number;
+}
+export interface IPane {
+    key: any;
+    element: HTMLElement;
+    index: number;
+    min: () => number;
+    max: () => number;
+    snap: () => number;
+    sz: () => number;
+    setSz: (number: number) => void;
+    setSplitterActive: (isActive: boolean) => void;
+    givenSize: number | null;
+    isReady: boolean;
+}