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/ajv/lib/dot/oneOf.jst

@@ -0,0 +1,54 @@
+{{# def.definitions }}
+{{# def.errors }}
+{{# def.setupKeyword }}
+{{# def.setupNextLevel }}
+
+{{
+  var $currentBaseId = $it.baseId
+    , $prevValid = 'prevValid' + $lvl
+    , $passingSchemas = 'passingSchemas' + $lvl;
+}}
+
+var {{=$errs}} = errors
+  , {{=$prevValid}} = false
+  , {{=$valid}} = false
+  , {{=$passingSchemas}} = null;
+
+{{# def.setCompositeRule }}
+
+{{~ $schema:$sch:$i }}
+  {{? {{# def.nonEmptySchema:$sch }} }}
+    {{
+      $it.schema = $sch;
+      $it.schemaPath = $schemaPath + '[' + $i + ']';
+      $it.errSchemaPath = $errSchemaPath + '/' + $i;
+    }}
+
+    {{# def.insertSubschemaCode }}
+  {{??}}
+    var {{=$nextValid}} = true;
+  {{?}}
+
+  {{? $i }}
+    if ({{=$nextValid}} && {{=$prevValid}}) {
+      {{=$valid}} = false;
+      {{=$passingSchemas}} = [{{=$passingSchemas}}, {{=$i}}];
+    } else {
+    {{ $closingBraces += '}'; }}
+  {{?}}
+
+    if ({{=$nextValid}}) {
+      {{=$valid}} = {{=$prevValid}} = true;
+      {{=$passingSchemas}} = {{=$i}};
+    }
+{{~}}
+
+{{# def.resetCompositeRule }}
+
+{{= $closingBraces }}
+
+if (!{{=$valid}}) {
+  {{# def.extraError:'oneOf' }}
+} else {
+  {{# def.resetErrors }}
+{{? it.opts.allErrors }} } {{?}}