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/deepmerge/index.js

@@ -0,0 +1,106 @@
+var defaultIsMergeableObject = require('is-mergeable-object')
+
+function emptyTarget(val) {
+	return Array.isArray(val) ? [] : {}
+}
+
+function cloneUnlessOtherwiseSpecified(value, options) {
+	return (options.clone !== false && options.isMergeableObject(value))
+		? deepmerge(emptyTarget(value), value, options)
+		: value
+}
+
+function defaultArrayMerge(target, source, options) {
+	return target.concat(source).map(function(element) {
+		return cloneUnlessOtherwiseSpecified(element, options)
+	})
+}
+
+function getMergeFunction(key, options) {
+	if (!options.customMerge) {
+		return deepmerge
+	}
+	var customMerge = options.customMerge(key)
+	return typeof customMerge === 'function' ? customMerge : deepmerge
+}
+
+function getEnumerableOwnPropertySymbols(target) {
+	return Object.getOwnPropertySymbols
+		? Object.getOwnPropertySymbols(target).filter(function(symbol) {
+			return Object.propertyIsEnumerable.call(target, symbol)
+		})
+		: []
+}
+
+function getKeys(target) {
+	return Object.keys(target).concat(getEnumerableOwnPropertySymbols(target))
+}
+
+function propertyIsOnObject(object, property) {
+	try {
+		return property in object
+	} catch(_) {
+		return false
+	}
+}
+
+// Protects from prototype poisoning and unexpected merging up the prototype chain.
+function propertyIsUnsafe(target, key) {
+	return propertyIsOnObject(target, key) // Properties are safe to merge if they don't exist in the target yet,
+		&& !(Object.hasOwnProperty.call(target, key) // unsafe if they exist up the prototype chain,
+			&& Object.propertyIsEnumerable.call(target, key)) // and also unsafe if they're nonenumerable.
+}
+
+function mergeObject(target, source, options) {
+	var destination = {}
+	if (options.isMergeableObject(target)) {
+		getKeys(target).forEach(function(key) {
+			destination[key] = cloneUnlessOtherwiseSpecified(target[key], options)
+		})
+	}
+	getKeys(source).forEach(function(key) {
+		if (propertyIsUnsafe(target, key)) {
+			return
+		}
+
+		if (propertyIsOnObject(target, key) && options.isMergeableObject(source[key])) {
+			destination[key] = getMergeFunction(key, options)(target[key], source[key], options)
+		} else {
+			destination[key] = cloneUnlessOtherwiseSpecified(source[key], options)
+		}
+	})
+	return destination
+}
+
+function deepmerge(target, source, options) {
+	options = options || {}
+	options.arrayMerge = options.arrayMerge || defaultArrayMerge
+	options.isMergeableObject = options.isMergeableObject || defaultIsMergeableObject
+	// cloneUnlessOtherwiseSpecified is added to `options` so that custom arrayMerge()
+	// implementations can use it. The caller may not replace it.
+	options.cloneUnlessOtherwiseSpecified = cloneUnlessOtherwiseSpecified
+
+	var sourceIsArray = Array.isArray(source)
+	var targetIsArray = Array.isArray(target)
+	var sourceAndTargetTypesMatch = sourceIsArray === targetIsArray
+
+	if (!sourceAndTargetTypesMatch) {
+		return cloneUnlessOtherwiseSpecified(source, options)
+	} else if (sourceIsArray) {
+		return options.arrayMerge(target, source, options)
+	} else {
+		return mergeObject(target, source, options)
+	}
+}
+
+deepmerge.all = function deepmergeAll(array, options) {
+	if (!Array.isArray(array)) {
+		throw new Error('first argument should be an array')
+	}
+
+	return array.reduce(function(prev, next) {
+		return deepmerge(prev, next, options)
+	}, {})
+}
+
+module.exports = deepmerge