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/enhanced-resolve/lib/util/graceful-fs-browser.js

@@ -0,0 +1,40 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+*/
+
+"use strict";
+
+// Browser stub for the default `graceful-fs` file system. A browser has no
+// ambient file system, so the convenience entry's default resolver has nothing
+// to read — pass your own `fileSystem` to `create()` /
+// `ResolverFactory.createResolver()` instead. Each method throws a clear error
+// if the default is actually used, while keeping the package able to bundle for
+// the browser (no Node `fs` dependency is pulled in).
+
+const message =
+	"enhanced-resolve: no default file system is available in the browser. " +
+	"Pass a `fileSystem` to `create()` or `ResolverFactory.createResolver()`.";
+
+/**
+ * @returns {never} always throws
+ */
+const unavailable = () => {
+	throw new Error(message);
+};
+
+// The same set of methods `CachedInputFileSystem` reads from the file system
+// (graceful-fs has no `readJson`/`readJsonSync`, so those stay undefined).
+module.exports = {
+	lstat: unavailable,
+	lstatSync: unavailable,
+	readFile: unavailable,
+	readFileSync: unavailable,
+	readdir: unavailable,
+	readdirSync: unavailable,
+	readlink: unavailable,
+	readlinkSync: unavailable,
+	realpath: unavailable,
+	realpathSync: unavailable,
+	stat: unavailable,
+	statSync: unavailable,
+};