Add validation to CPNI and STIR/SHAKEN intake steps

- CPNI: requires either clean compliance checkbox OR issues section opened
- STIR/SHAKEN: requires selecting implementation status before advancing

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

site/src/components/intake/steps/CPNIStep.astro

@@ -118,6 +118,17 @@
     const PW = (window as any).PWIntake;
     if (PW.steps[PW.get().step_index] !== "cpni_questions") return;
 
+    const errEl = document.getElementById("pw-cpni-err") as HTMLDivElement;
+
+    // Validate: if not clean, must have opened issues section
+    if (!cleanBox.checked && !issuesEl.open) {
+      errEl.hidden = false;
+      errEl.textContent = "Please either confirm clean compliance or expand the issues section and provide details.";
+      evt.preventDefault();
+      return;
+    }
+    errEl.hidden = true;
+
     const g = (id: string) => (document.getElementById(id) as HTMLInputElement)?.value || "";
 
     if (cleanBox.checked) {

site/src/components/intake/steps/STIRShakenStep.astro

@@ -24,6 +24,8 @@
 
   <label class="pw-field">Upstream voice provider (if partial / robocall-mitigation-only)</label>
   <input type="text" id="pw-ss-upstream" class="pw-input" placeholder="e.g. Bandwidth.com, VoIP Innovations" />
+
+  <div id="pw-ss-err" class="pw-err" hidden></div>
 </div>
 
 <style>
@@ -31,6 +33,7 @@
   .pw-help    { color: #64748b; font-size: 0.9rem; margin-bottom: 1rem; }
   .pw-field   { display: block; font-weight: 600; margin: 0.8rem 0 0.2rem; font-size: 0.88rem; }
   .pw-input   { width: 100%; padding: 0.5rem 0.7rem; border: 1px solid #cbd5e1; border-radius: 6px; font-size: 0.93rem; }
+  .pw-err     { color: #b91c1c; margin-top: 0.75rem; font-size: 0.9rem; }
 </style>
 
 <script>
@@ -45,8 +48,19 @@
   window.addEventListener("pw:step-next", (evt: any) => {
     const PW = (window as any).PWIntake;
     if (PW.steps[PW.get().step_index] !== "stir_shaken") return;
+
+    const status = g<HTMLSelectElement>("pw-ss-status").value;
+    if (!status) {
+      const errEl = document.getElementById("pw-ss-err");
+      if (errEl) { errEl.hidden = false; errEl.textContent = "Please select your STIR/SHAKEN implementation status."; }
+      evt.preventDefault();
+      return;
+    }
+    const errEl2 = document.getElementById("pw-ss-err");
+    if (errEl2) errEl2.hidden = true;
+
     PW.patchIntakeData({
-      target_stir_shaken_status: g<HTMLSelectElement>("pw-ss-status").value,
+      target_stir_shaken_status: status,
       sti_ca_vendor: g<HTMLInputElement>("pw-ss-vendor").value.trim(),
       upstream_provider_name: g<HTMLInputElement>("pw-ss-upstream").value.trim(),
     });