fix(security): tab-nabbing hardening + /acl self-lockout guard (SEC-3/4)

SEC-3: add `noopener,noreferrer` to the 5 `window.open(_blank)` sites that
don't use the returned handle (UserChips, OidcManageAccount, OtherDevices x2,
Verification), closing reverse tab-nabbing. SSOStage is intentionally excluded —
it needs the window handle + intact opener for its origin-checked SSO
postMessage handshake.

SEC-4: guard the `/acl` slash command against bricking the room.
- Extract the ACL glob helpers (isValidServerPattern/globToRegExp/matchesAnyGlob)
  from RoomServerACL into a shared utils/serverAcl.ts (+ unit test) so the
  command and the settings editor validate identically.
- Default a MISSING allow list to `*` only when the room has NO existing ACL
  (a first `/acl -d x` otherwise sent `allow: []`, which bricks the room); an
  existing ACL's absent/empty allow is preserved, not silently widened.
- Reject invalid globs; fail CLOSED on the universally-catastrophic cases
  (empty allow, or a `*` deny) even when the local domain is unknown; and reject
  any change that would ban this homeserver (self-lockout).

Guard hardened per two review passes (fail-closed on unknown domain; no silent
federation widening).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/utils/serverAcl.test.ts

@@ -0,0 +1,44 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { isValidServerPattern, globToRegExp, matchesAnyGlob } from './serverAcl';
+
+test('isValidServerPattern: accepts hostnames, IPs, and globs', () => {
+  for (const v of [
+    '*',
+    '*.example.com',
+    'matrix.org',
+    '1.2.3.*',
+    '10.0.0.?',
+    '*.evil.*',
+    '*bad*',
+  ]) {
+    assert.equal(isValidServerPattern(v), true, v);
+  }
+});
+
+test('isValidServerPattern: rejects empty, malformed, and non-glob junk', () => {
+  for (const v of ['', '   ', '.foo', 'foo.', 'a..b', '-', ':', 'under_score', 'a,b', 'a b']) {
+    assert.equal(isValidServerPattern(v), false, v);
+  }
+});
+
+test('globToRegExp: * = any run, ? = single char, other metachars escaped', () => {
+  assert.equal(globToRegExp('*').test('anything.org'), true);
+  assert.equal(globToRegExp('*.evil.com').test('a.evil.com'), true);
+  assert.equal(globToRegExp('*.evil.com').test('evil.com'), false); // needs the leading label
+  assert.equal(globToRegExp('1.2.3.?').test('1.2.3.4'), true);
+  assert.equal(globToRegExp('1.2.3.?').test('1.2.3.45'), false);
+  // The dot is a literal, not a regex wildcard.
+  assert.equal(globToRegExp('a.b').test('axb'), false);
+});
+
+test('globToRegExp: case-insensitive (hostnames + Synapse IGNORECASE)', () => {
+  assert.equal(globToRegExp('MATRIX.foo.org').test('matrix.foo.org'), true);
+});
+
+test('matchesAnyGlob: true if any glob matches (self-ban detection)', () => {
+  assert.equal(matchesAnyGlob('lotusguild.org', ['*']), true);
+  assert.equal(matchesAnyGlob('lotusguild.org', ['*.evil.com', 'lotus*.org']), true);
+  assert.equal(matchesAnyGlob('lotusguild.org', ['*.evil.com']), false);
+  assert.equal(matchesAnyGlob('lotusguild.org', []), false);
+});

src/app/utils/serverAcl.ts

@@ -0,0 +1,52 @@
+// Shared helpers for `m.room.server_acl` server-name globs, used by both the
+// Room Settings ACL editor and the `/acl` slash command so their validation and
+// self-lockout detection stay identical.
+
+/**
+ * Validate a server-name glob for an ACL entry.
+ *
+ * Matrix ACL `allow`/`deny` entries are globs where `*` (any run of chars) and
+ * `?` (single char) may appear ANYWHERE — e.g. `*`, `*.example.com`,
+ * `1.2.3.*`, `10.0.0.?`, `*.evil.*`, `*bad*`. We therefore validate the *glob*
+ * rather than a concrete hostname:
+ *   - reject empty / whitespace-only
+ *   - allow only hostname/IP chars plus the wildcards `*` and `?`
+ *     (letters, digits, dots, hyphens, colons for ports/IPv6 — NO underscore)
+ *   - reject consecutive/leading/trailing dots (`...`, `.foo`, `foo.`)
+ *   - reject entries with no alphanumeric or wildcard char (bare `-`, lone `:`)
+ */
+export function isValidServerPattern(value: string): boolean {
+  const v = value.trim();
+  if (!v) return false;
+  // Only hostname/IP glob chars — wildcards may appear at any position.
+  if (!/^[A-Za-z0-9.:*?-]+$/.test(v)) return false;
+  // Structural rules for the dotted parts.
+  if (v.startsWith('.') || v.endsWith('.') || v.includes('..')) return false;
+  // Must carry actual signal — reject pure punctuation like `-`, `:` or `-.-`.
+  if (!/[A-Za-z0-9*?]/.test(v)) return false;
+  return true;
+}
+
+/**
+ * Convert an ACL glob (`*` = any run, `?` = single char) to an anchored RegExp,
+ * escaping every other regex metacharacter. Used only for local self-ban
+ * detection — never sent to the server.
+ */
+export function globToRegExp(glob: string): RegExp {
+  const escaped = glob.replace(/[.+^${}()|[\]\\]/g, '\\$&');
+  const pattern = escaped.replace(/\*/g, '.*').replace(/\?/g, '.');
+  // Case-INsensitive: Synapse's glob_to_regex uses IGNORECASE and hostnames are
+  // case-insensitive, so a deny like `MATRIX.foo.org` must still be detected as
+  // self-banning `matrix.foo.org` (otherwise the warning is a false negative).
+  return new RegExp(`^${pattern}$`, 'i');
+}
+
+export function matchesAnyGlob(domain: string, globs: string[]): boolean {
+  return globs.some((glob) => {
+    try {
+      return globToRegExp(glob).test(domain);
+    } catch {
+      return false;
+    }
+  });
+}