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/eslint/lib/rules/no-nonoctal-decimal-escape.js

@@ -0,0 +1,176 @@
+/**
+ * @fileoverview Rule to disallow `\8` and `\9` escape sequences in string literals.
+ * @author Milos Djermanovic
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Typedefs
+//------------------------------------------------------------------------------
+
+/**
+ * @import { SourceRange } from "@eslint/core";
+ */
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+const QUICK_TEST_REGEX = /\\[89]/u;
+
+/**
+ * Returns unicode escape sequence that represents the given character.
+ * @param {string} character A single code unit.
+ * @returns {string} "\uXXXX" sequence.
+ */
+function getUnicodeEscape(character) {
+	return `\\u${character.charCodeAt(0).toString(16).padStart(4, "0")}`;
+}
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+/** @type {import('../types').Rule.RuleModule} */
+module.exports = {
+	meta: {
+		type: "suggestion",
+
+		docs: {
+			description:
+				"Disallow `\\8` and `\\9` escape sequences in string literals",
+			recommended: true,
+			url: "https://eslint.org/docs/latest/rules/no-nonoctal-decimal-escape",
+		},
+
+		hasSuggestions: true,
+
+		schema: [],
+
+		messages: {
+			decimalEscape: "Don't use '{{decimalEscape}}' escape sequence.",
+
+			// suggestions
+			refactor:
+				"Replace '{{original}}' with '{{replacement}}'. This maintains the current functionality.",
+			escapeBackslash:
+				"Replace '{{original}}' with '{{replacement}}' to include the actual backslash character.",
+		},
+	},
+
+	create(context) {
+		const sourceCode = context.sourceCode;
+
+		/**
+		 * Creates a new Suggestion object.
+		 * @param {string} messageId "refactor" or "escapeBackslash".
+		 * @param {SourceRange} range The range to replace.
+		 * @param {string} replacement New text for the range.
+		 * @returns {Object} Suggestion
+		 */
+		function createSuggestion(messageId, range, replacement) {
+			return {
+				messageId,
+				data: {
+					original: sourceCode.getText().slice(...range),
+					replacement,
+				},
+				fix(fixer) {
+					return fixer.replaceTextRange(range, replacement);
+				},
+			};
+		}
+
+		return {
+			Literal(node) {
+				if (typeof node.value !== "string") {
+					return;
+				}
+
+				if (!QUICK_TEST_REGEX.test(node.raw)) {
+					return;
+				}
+
+				const regex =
+					/(?:[^\\]|(?<previousEscape>\\.))*?(?<decimalEscape>\\[89])/suy;
+				let match;
+
+				while ((match = regex.exec(node.raw))) {
+					const { previousEscape, decimalEscape } = match.groups;
+					const decimalEscapeRangeEnd =
+						node.range[0] + match.index + match[0].length;
+					const decimalEscapeRangeStart =
+						decimalEscapeRangeEnd - decimalEscape.length;
+					const decimalEscapeRange = [
+						decimalEscapeRangeStart,
+						decimalEscapeRangeEnd,
+					];
+					const suggest = [];
+
+					// When `regex` is matched, `previousEscape` can only capture characters adjacent to `decimalEscape`
+					if (previousEscape === "\\0") {
+						/*
+						 * Now we have a NULL escape "\0" immediately followed by a decimal escape, e.g.: "\0\8".
+						 * Fixing this to "\08" would turn "\0" into a legacy octal escape. To avoid producing
+						 * an octal escape while fixing a decimal escape, we provide different suggestions.
+						 */
+						suggest.push(
+							createSuggestion(
+								// "\0\8" -> "\u00008"
+								"refactor",
+								[
+									decimalEscapeRangeStart -
+										previousEscape.length,
+									decimalEscapeRangeEnd,
+								],
+								`${getUnicodeEscape("\0")}${decimalEscape[1]}`,
+							),
+							createSuggestion(
+								// "\8" -> "\u0038"
+								"refactor",
+								decimalEscapeRange,
+								getUnicodeEscape(decimalEscape[1]),
+							),
+						);
+					} else {
+						suggest.push(
+							createSuggestion(
+								// "\8" -> "8"
+								"refactor",
+								decimalEscapeRange,
+								decimalEscape[1],
+							),
+						);
+					}
+
+					suggest.push(
+						createSuggestion(
+							// "\8" -> "\\8"
+							"escapeBackslash",
+							decimalEscapeRange,
+							`\\${decimalEscape}`,
+						),
+					);
+
+					context.report({
+						node,
+						loc: {
+							start: sourceCode.getLocFromIndex(
+								decimalEscapeRangeStart,
+							),
+							end: sourceCode.getLocFromIndex(
+								decimalEscapeRangeEnd,
+							),
+						},
+						messageId: "decimalEscape",
+						data: {
+							decimalEscape,
+						},
+						suggest,
+					});
+				}
+			},
+		};
+	},
+};