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/yaml/dist/stringify/stringifyDocument.js

@@ -0,0 +1,87 @@
+'use strict';
+
+var identity = require('../nodes/identity.js');
+var stringify = require('./stringify.js');
+var stringifyComment = require('./stringifyComment.js');
+
+function stringifyDocument(doc, options) {
+    const lines = [];
+    let hasDirectives = options.directives === true;
+    if (options.directives !== false && doc.directives) {
+        const dir = doc.directives.toString(doc);
+        if (dir) {
+            lines.push(dir);
+            hasDirectives = true;
+        }
+        else if (doc.directives.docStart)
+            hasDirectives = true;
+    }
+    if (hasDirectives)
+        lines.push('---');
+    const ctx = stringify.createStringifyContext(doc, options);
+    const { commentString } = ctx.options;
+    if (doc.commentBefore) {
+        if (lines.length !== 1)
+            lines.unshift('');
+        const cs = commentString(doc.commentBefore);
+        lines.unshift(stringifyComment.indentComment(cs, ''));
+    }
+    let chompKeep = false;
+    let contentComment = null;
+    if (doc.contents) {
+        if (identity.isNode(doc.contents)) {
+            if (doc.contents.spaceBefore && hasDirectives)
+                lines.push('');
+            if (doc.contents.commentBefore) {
+                const cs = commentString(doc.contents.commentBefore);
+                lines.push(stringifyComment.indentComment(cs, ''));
+            }
+            // top-level block scalars need to be indented if followed by a comment
+            ctx.forceBlockIndent = !!doc.comment;
+            contentComment = doc.contents.comment;
+        }
+        const onChompKeep = contentComment ? undefined : () => (chompKeep = true);
+        let body = stringify.stringify(doc.contents, ctx, () => (contentComment = null), onChompKeep);
+        if (contentComment)
+            body += stringifyComment.lineComment(body, '', commentString(contentComment));
+        if ((body[0] === '|' || body[0] === '>') &&
+            lines[lines.length - 1] === '---') {
+            // Top-level block scalars with a preceding doc marker ought to use the
+            // same line for their header.
+            lines[lines.length - 1] = `--- ${body}`;
+        }
+        else
+            lines.push(body);
+    }
+    else {
+        lines.push(stringify.stringify(doc.contents, ctx));
+    }
+    if (doc.directives?.docEnd) {
+        if (doc.comment) {
+            const cs = commentString(doc.comment);
+            if (cs.includes('\n')) {
+                lines.push('...');
+                lines.push(stringifyComment.indentComment(cs, ''));
+            }
+            else {
+                lines.push(`... ${cs}`);
+            }
+        }
+        else {
+            lines.push('...');
+        }
+    }
+    else {
+        let dc = doc.comment;
+        if (dc && chompKeep)
+            dc = dc.replace(/^\n+/, '');
+        if (dc) {
+            if ((!chompKeep || contentComment) && lines[lines.length - 1] !== '')
+                lines.push('');
+            lines.push(stringifyComment.indentComment(commentString(dc), ''));
+        }
+    }
+    return lines.join('\n') + '\n';
+}
+
+exports.stringifyDocument = stringifyDocument;