feat(users): OTP delivery method picker on user creation + post-login agreement

Create User dialog now has a mandatory Email/Mobile OTP delivery method
picker (styled as a pill toggle) alongside the existing fields.

Adds a new post-login agreement acceptance dialog: right after the existing
2FA flow (TwoFactorAuthenticationComponent) succeeds, or immediately after
login for users without 2FA, the user must accept the bank's current
agreement/disclaimer at least once before reaching the app.

Also adds a "Manage User Agreement" admin screen (System section) to publish
versioned agreement text without a code deploy.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/login/agreement-accept/agreement-accept.component.html

@@ -0,0 +1,71 @@
+<!--
+  Copyright since 2025 Mifos Initiative
+
+  This Source Code Form is subject to the terms of the Mozilla Public
+  License, v. 2.0. If a copy of the MPL was not distributed with this
+  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+-->
+
+<div class="aga-card">
+  <div class="aga-icon">
+    <fa-icon icon="file-signature"></fa-icon>
+  </div>
+
+  <h2 class="aga-title">Terms &amp; Agreement</h2>
+  <p class="aga-sub">
+    @if (loading) {
+      Loading the agreement…
+    } @else if (loadErrorMessage) {
+      We couldn't load the agreement.
+    } @else {
+      Please read the agreement below before continuing.
+    }
+  </p>
+
+  @if (loading) {
+    <div class="aga-loading">
+      <mat-spinner diameter="32"></mat-spinner>
+    </div>
+  } @else if (loadErrorMessage) {
+    <div class="aga-error">
+      <fa-icon icon="exclamation-circle"></fa-icon>
+      {{ loadErrorMessage }}
+    </div>
+    <button type="button" class="aga-btn aga-btn--ghost" (click)="loadAgreement()">
+      <fa-icon icon="sync-alt"></fa-icon>
+      <span>Try Again</span>
+    </button>
+  } @else {
+    <div class="aga-agreement">
+      <h3 class="aga-agreement__title">{{ agreementTitle }}</h3>
+      <div class="aga-agreement__body">{{ agreementBody }}</div>
+    </div>
+
+    <label class="aga-check">
+      <input type="checkbox" [checked]="accepted" (change)="toggleAccepted()" />
+      <span>I have read and agree to the above</span>
+    </label>
+
+    @if (submitErrorMessage) {
+      <div class="aga-error">
+        <fa-icon icon="exclamation-circle"></fa-icon>
+        {{ submitErrorMessage }}
+      </div>
+    }
+
+    <button
+      type="button"
+      class="aga-btn aga-btn--primary"
+      [disabled]="!accepted || submitting"
+      (click)="acceptAndContinue()"
+    >
+      @if (submitting) {
+        <mat-spinner diameter="20"></mat-spinner>
+        <span>Submitting…</span>
+      } @else {
+        <fa-icon icon="check-circle"></fa-icon>
+        <span>Accept &amp; Continue</span>
+      }
+    </button>
+  }
+</div>