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/postcss/lib/previous-map.d.ts

@@ -0,0 +1,80 @@
+import { SourceMapConsumer } from 'source-map-js'
+
+import { ProcessOptions } from './postcss.js'
+
+declare namespace PreviousMap {
+  export { PreviousMap_ as default }
+}
+
+/**
+ * Source map information from input CSS.
+ * For example, source map after Sass compiler.
+ *
+ * This class will automatically find source map in input CSS or in file system
+ * near input file (according `from` option).
+ *
+ * ```js
+ * const root = parse(css, { from: 'a.sass.css' })
+ * root.input.map //=> PreviousMap
+ * ```
+ */
+declare class PreviousMap_ {
+  /**
+   * `sourceMappingURL` content.
+   */
+  annotation?: string
+
+  /**
+   * The CSS source identifier. Contains `Input#file` if the user
+   * set the `from` option, or `Input#id` if they did not.
+   */
+  file?: string
+
+  /**
+   * Was source map inlined by data-uri to input CSS.
+   */
+  inline: boolean
+
+  /**
+   * Path to source map file.
+   */
+  mapFile?: string
+
+  /**
+   * The directory with source map file, if source map is in separated file.
+   */
+  root?: string
+
+  /**
+   * Source map file content.
+   */
+  text?: string
+
+  /**
+   * @param css  Input CSS source.
+   * @param opts Process options.
+   */
+  constructor(css: string, opts?: ProcessOptions)
+
+  /**
+   * Create a instance of `SourceMapGenerator` class
+   * from the `source-map` library to work with source map information.
+   *
+   * It is lazy method, so it will create object only on first call
+   * and then it will use cache.
+   *
+   * @return Object with source map information.
+   */
+  consumer(): SourceMapConsumer
+
+  /**
+   * Does source map contains `sourcesContent` with input source text.
+   *
+   * @return Is `sourcesContent` present.
+   */
+  withContent(): boolean
+}
+
+declare class PreviousMap extends PreviousMap_ {}
+
+export = PreviousMap