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/whatwg-url/lib/URLSearchParams-impl.js

@@ -0,0 +1,135 @@
+"use strict";
+const urlencoded = require("./urlencoded");
+
+exports.implementation = class URLSearchParamsImpl {
+  constructor(globalObject, constructorArgs, { doNotStripQMark = false }) {
+    let init = constructorArgs[0];
+    this._list = [];
+    this._url = null;
+
+    if (!doNotStripQMark && typeof init === "string" && init[0] === "?") {
+      init = init.slice(1);
+    }
+
+    if (Array.isArray(init)) {
+      for (const pair of init) {
+        if (pair.length !== 2) {
+          throw new TypeError("Failed to construct 'URLSearchParams': parameter 1 sequence's element does not " +
+                              "contain exactly two elements.");
+        }
+        this._list.push([pair[0], pair[1]]);
+      }
+    } else if (typeof init === "object" && Object.getPrototypeOf(init) === null) {
+      for (const name of Object.keys(init)) {
+        const value = init[name];
+        this._list.push([name, value]);
+      }
+    } else {
+      this._list = urlencoded.parseUrlencodedString(init);
+    }
+  }
+
+  _updateSteps() {
+    if (this._url !== null) {
+      let serializedQuery = urlencoded.serializeUrlencoded(this._list);
+      if (serializedQuery === "") {
+        serializedQuery = null;
+      }
+
+      this._url._url.query = serializedQuery;
+    }
+  }
+
+  get size() {
+    return this._list.length;
+  }
+
+  append(name, value) {
+    this._list.push([name, value]);
+    this._updateSteps();
+  }
+
+  delete(name, value) {
+    let i = 0;
+    while (i < this._list.length) {
+      if (this._list[i][0] === name && (value === undefined || this._list[i][1] === value)) {
+        this._list.splice(i, 1);
+      } else {
+        i++;
+      }
+    }
+    this._updateSteps();
+  }
+
+  get(name) {
+    for (const tuple of this._list) {
+      if (tuple[0] === name) {
+        return tuple[1];
+      }
+    }
+    return null;
+  }
+
+  getAll(name) {
+    const output = [];
+    for (const tuple of this._list) {
+      if (tuple[0] === name) {
+        output.push(tuple[1]);
+      }
+    }
+    return output;
+  }
+
+  has(name, value) {
+    for (const tuple of this._list) {
+      if (tuple[0] === name && (value === undefined || tuple[1] === value)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  set(name, value) {
+    let found = false;
+    let i = 0;
+    while (i < this._list.length) {
+      if (this._list[i][0] === name) {
+        if (found) {
+          this._list.splice(i, 1);
+        } else {
+          found = true;
+          this._list[i][1] = value;
+          i++;
+        }
+      } else {
+        i++;
+      }
+    }
+    if (!found) {
+      this._list.push([name, value]);
+    }
+    this._updateSteps();
+  }
+
+  sort() {
+    this._list.sort((a, b) => {
+      if (a[0] < b[0]) {
+        return -1;
+      }
+      if (a[0] > b[0]) {
+        return 1;
+      }
+      return 0;
+    });
+
+    this._updateSteps();
+  }
+
+  [Symbol.iterator]() {
+    return this._list[Symbol.iterator]();
+  }
+
+  toString() {
+    return urlencoded.serializeUrlencoded(this._list);
+  }
+};