Add calculator UX enhancements and submission tracking

- Button loading spinner + disable on submit to prevent duplicate AI calls
- Email field and opt-in consent checkbox on calculator form (checked by default)
- Privacy assurance blurb below opt-in
- Refinement blurb on results screen explaining live cash-flow optimization
- calc_submissions SQLite table stores form inputs, computed results, AI text, email, opt-in
- GET /api/calc-submissions endpoint (x-admin-key protected) to retrieve submissions

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

server.js

@@ -53,6 +53,25 @@ db.exec(`
   );
 `);
 
+db.exec(`
+  CREATE TABLE IF NOT EXISTS calc_submissions (
+    id                INTEGER PRIMARY KEY AUTOINCREMENT,
+    email             TEXT,
+    opt_in            INTEGER DEFAULT 1,
+    homesites         REAL,
+    property_type     TEXT,
+    annual_income     REAL,
+    payment_freq      TEXT,
+    reserve_funds     REAL,
+    interest_2025     REAL,
+    total_potential   REAL,
+    op_interest       REAL,
+    res_interest      REAL,
+    ai_recommendation TEXT,
+    created_at        TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ','now'))
+  );
+`);
+
 // Migrate existing DBs: add new columns if they don't exist yet
 const cols = db.pragma('table_info(leads)').map(c => c.name);
 if (!cols.includes('org_name'))      db.exec('ALTER TABLE leads ADD COLUMN org_name TEXT');
@@ -67,6 +86,19 @@ const insertLead = db.prepare(`
 
 const findByEmail = db.prepare(`SELECT id FROM leads WHERE email = ? LIMIT 1`);
 
+const insertCalcSubmission = db.prepare(`
+  INSERT INTO calc_submissions
+    (email, opt_in, homesites, property_type, annual_income, payment_freq,
+     reserve_funds, interest_2025, total_potential, op_interest, res_interest, ai_recommendation)
+  VALUES
+    (@email, @optIn, @homesites, @propertyType, @annualIncome, @paymentFreq,
+     @reserveFunds, @interest2025, @totalPotential, @opInterest, @resInterest, @aiRecommendation)
+`);
+
+const getAllCalcSubmissions = db.prepare(`
+  SELECT * FROM calc_submissions ORDER BY created_at DESC
+`);
+
 const getAllLeads = db.prepare(`
   SELECT id, first_name, last_name, email, org_name, state, role, unit_count, beta_interest, source, created_at
   FROM leads
@@ -140,11 +172,36 @@ app.get('/api/leads', (req, res) => {
 
 // POST /api/calculate  — AI-powered investment recommendation
 app.post('/api/calculate', async (req, res) => {
+  function saveCalcSubmission(aiRecommendation) {
+    try {
+      insertCalcSubmission.run({
+        email:           email?.trim() || null,
+        optIn:           optIn ? 1 : 0,
+        homesites:       homesites || null,
+        propertyType:    propertyType || null,
+        annualIncome:    annualIncome || null,
+        paymentFreq:     paymentFreq || null,
+        reserveFunds:    reserveFunds || null,
+        interest2025:    interest2025 || null,
+        totalPotential:  totalPotential || null,
+        opInterest:      opInterest || null,
+        resInterest:     resInterest || null,
+        aiRecommendation: aiRecommendation || null,
+      });
+    } catch (err) {
+      console.error('Failed to save calc submission:', err.message);
+    }
+  }
+
   if (!aiClient) {
+    saveCalcSubmission(null);
     return res.status(503).json({ error: 'AI service not configured.' });
   }
 
-  const { homesites, propertyType, annualIncome, paymentFreq, reserveFunds, interest2025 } = req.body ?? {};
+  const {
+    homesites, propertyType, annualIncome, paymentFreq, reserveFunds, interest2025,
+    email, optIn, totalPotential, opInterest, resInterest,
+  } = req.body ?? {};
 
   if (!homesites || !annualIncome) {
     return res.status(400).json({ error: 'homesites and annualIncome are required.' });
@@ -185,13 +242,25 @@ Keep the tone professional and factual. No bullet points — flowing paragraph o
 
     if (AI_DEBUG) console.log('[AI_DEBUG] response:', text);
 
+    saveCalcSubmission(text);
     res.json({ recommendation: text });
   } catch (err) {
     console.error('AI API error:', err.message);
+    saveCalcSubmission(null);
     res.status(502).json({ error: 'AI service unavailable. Showing estimated result.' });
   }
 });
 
+// GET /api/calc-submissions  — internal: list all calculator submissions
+app.get('/api/calc-submissions', (req, res) => {
+  const secret = req.headers['x-admin-key'];
+  if (!secret || secret !== process.env.ADMIN_KEY) {
+    return res.status(401).json({ error: 'Unauthorized.' });
+  }
+  const rows = getAllCalcSubmissions.all();
+  res.json({ count: rows.length, submissions: rows });
+});
+
 // Health check
 app.get('/api/health', (_req, res) => res.json({ status: 'ok', ts: new Date().toISOString() }));