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/vitest/dist/chunks/git.B5SDxu-n.js

@@ -0,0 +1,69 @@
+import { resolve } from 'pathe';
+import { x } from 'tinyexec';
+
+class VitestGit {
+  constructor(cwd) {
+    this.cwd = cwd;
+  }
+  root;
+  async resolveFilesWithGitCommand(args) {
+    let result;
+    try {
+      result = await x("git", args, { nodeOptions: { cwd: this.root } });
+    } catch (e) {
+      e.message = e.stderr;
+      throw e;
+    }
+    return result.stdout.split("\n").filter((s) => s !== "").map((changedPath) => resolve(this.root, changedPath));
+  }
+  async findChangedFiles(options) {
+    const root = await this.getRoot(this.cwd);
+    if (!root) {
+      return null;
+    }
+    this.root = root;
+    const changedSince = options.changedSince;
+    if (typeof changedSince === "string") {
+      const [committed, staged2, unstaged2] = await Promise.all([
+        this.getFilesSince(changedSince),
+        this.getStagedFiles(),
+        this.getUnstagedFiles()
+      ]);
+      return [...committed, ...staged2, ...unstaged2];
+    }
+    const [staged, unstaged] = await Promise.all([
+      this.getStagedFiles(),
+      this.getUnstagedFiles()
+    ]);
+    return [...staged, ...unstaged];
+  }
+  getFilesSince(hash) {
+    return this.resolveFilesWithGitCommand([
+      "diff",
+      "--name-only",
+      `${hash}...HEAD`
+    ]);
+  }
+  getStagedFiles() {
+    return this.resolveFilesWithGitCommand(["diff", "--cached", "--name-only"]);
+  }
+  getUnstagedFiles() {
+    return this.resolveFilesWithGitCommand([
+      "ls-files",
+      "--other",
+      "--modified",
+      "--exclude-standard"
+    ]);
+  }
+  async getRoot(cwd) {
+    const args = ["rev-parse", "--show-cdup"];
+    try {
+      const result = await x("git", args, { nodeOptions: { cwd } });
+      return resolve(cwd, result.stdout.trim());
+    } catch {
+      return null;
+    }
+  }
+}
+
+export { VitestGit };