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/zimmerframe/src/walk.js

@@ -0,0 +1,168 @@
+/** @import { Context, Visitor, Visitors } from './types.js' */
+
+/**
+ * @template {{ type: string }} T
+ * @template {Record<string, any> | null} U
+ * @param {T} node
+ * @param {U} state
+ * @param {Visitors<T, U>} visitors
+ */
+export function walk(node, state, visitors) {
+	const universal = visitors._;
+
+	let stopped = false;
+
+	/** @type {Visitor<T, U, T>} _ */
+	function default_visitor(_, { next, state }) {
+		next(state);
+	}
+
+	/**
+	 * @param {T} node
+	 * @param {T[]} path
+	 * @param {U} state
+	 * @returns {T | undefined}
+	 */
+	function visit(node, path, state) {
+		// Don't return the node here or it could lead to false-positive mutation detection
+		if (stopped) return;
+		if (!node.type) return;
+
+		/** @type {T | void} */
+		let result;
+
+		/** @type {Record<string, any>} */
+		const mutations = {};
+
+		/** @type {Context<T, U>} */
+		const context = {
+			path,
+			state,
+			next: (next_state = state) => {
+				path.push(node);
+				for (const key in node) {
+					if (key === 'type') continue;
+
+					const child_node = node[key];
+					if (child_node && typeof child_node === 'object') {
+						if (Array.isArray(child_node)) {
+							/** @type {Record<number, T>} */
+							const array_mutations = {};
+							const len = child_node.length;
+
+							let mutated = false;
+
+							for (let i = 0; i < len; i++) {
+								const node = child_node[i];
+								if (node && typeof node === 'object') {
+									const result = visit(node, path, next_state);
+									if (result) {
+										array_mutations[i] = result;
+										mutated = true;
+									}
+								}
+							}
+
+							if (mutated) {
+								mutations[key] = child_node.map(
+									(node, i) => array_mutations[i] ?? node
+								);
+							}
+						} else {
+							const result = visit(
+								/** @type {T} */ (child_node),
+								path,
+								next_state
+							);
+
+							// @ts-ignore
+							if (result) {
+								mutations[key] = result;
+							}
+						}
+					}
+				}
+				path.pop();
+
+				if (Object.keys(mutations).length > 0) {
+					return apply_mutations(node, mutations);
+				}
+			},
+			stop: () => {
+				stopped = true;
+			},
+			visit: (next_node, next_state = state) => {
+				path.push(node);
+				const result = visit(next_node, path, next_state) ?? next_node;
+				path.pop();
+				return result;
+			}
+		};
+
+		let visitor = /** @type {Visitor<T, U, T>} */ (
+			visitors[/** @type {T['type']} */ (node.type)] ?? default_visitor
+		);
+
+		if (universal) {
+			/** @type {T | void} */
+			let inner_result;
+
+			result = universal(node, {
+				...context,
+				/** @param {U} next_state */
+				next: (next_state = state) => {
+					state = next_state; // make it the default for subsequent specialised visitors
+
+					inner_result = visitor(node, {
+						...context,
+						state: next_state
+					});
+
+					return inner_result;
+				}
+			});
+
+			// @ts-expect-error TypeScript doesn't understand that `context.next(...)` is called immediately
+			if (!result && inner_result) {
+				result = inner_result;
+			}
+		} else {
+			result = visitor(node, context);
+		}
+
+		if (!result) {
+			if (Object.keys(mutations).length > 0) {
+				result = apply_mutations(node, mutations);
+			}
+		}
+
+		if (result) {
+			return result;
+		}
+	}
+
+	return visit(node, [], state) ?? node;
+}
+
+/**
+ * @template {Record<string, any>} T
+ * @param {T} node
+ * @param {Record<string, any>} mutations
+ * @returns {T}
+ */
+function apply_mutations(node, mutations) {
+	/** @type {Record<string, any>} */
+	const obj = {};
+
+	const descriptors = Object.getOwnPropertyDescriptors(node);
+
+	for (const key in descriptors) {
+		Object.defineProperty(obj, key, descriptors[key]);
+	}
+
+	for (const key in mutations) {
+		obj[key] = mutations[key];
+	}
+
+	return /** @type {T} */ (obj);
+}