v0.4.0: Remove free tier, add public demo endpoint with watermark

- Remove free account signup flow entirely
- Add POST /v1/demo/html and /v1/demo/markdown (public, no auth)
- Demo: 5 requests/hour per IP, 50KB body limit, watermarked PDFs
- Landing page: interactive playground replaces 'Get Free API Key'
- Pricing: Demo (free) + Pro (€9/mo), no more Free tier
- /v1/signup returns 410 Gone with redirect to demo/pro
- Keep /v1/recover for existing Pro users
- Update JSON-LD, API discovery, verify page text

public/index.html

@@ -16,10 +16,10 @@
 <meta name="twitter:image" content="https://docfast.dev/og-image.png">
 <link rel="canonical" href="https://docfast.dev/">
 <script type="application/ld+json">
-{"@context":"https://schema.org","@type":"SoftwareApplication","name":"DocFast","url":"https://docfast.dev","applicationCategory":"DeveloperApplication","operatingSystem":"Web","description":"Convert HTML and Markdown to beautiful PDFs with a simple API call. Fast, reliable, developer-friendly.","offers":[{"@type":"Offer","price":"0","priceCurrency":"EUR","name":"Free","description":"100 PDFs/month"},{"@type":"Offer","price":"9","priceCurrency":"EUR","name":"Pro","description":"5,000 PDFs/month","billingIncrement":"P1M"}]}
+{"@context":"https://schema.org","@type":"SoftwareApplication","name":"DocFast","url":"https://docfast.dev","applicationCategory":"DeveloperApplication","operatingSystem":"Web","description":"Convert HTML and Markdown to beautiful PDFs with a simple API call. Fast, reliable, developer-friendly.","offers":[{"@type":"Offer","price":"9","priceCurrency":"EUR","name":"Pro","description":"5,000 PDFs/month","billingIncrement":"P1M"}]}
 </script>
 <script type="application/ld+json">
-{"@context":"https://schema.org","@type":"WebApplication","name":"DocFast","url":"https://docfast.dev","browserRequirements":"Requires JavaScript. Requires HTML5.","applicationCategory":"DeveloperApplication","operatingSystem":"All","offers":[{"@type":"Offer","price":"0","priceCurrency":"EUR","name":"Free Tier","description":"100 PDFs per month, all endpoints included"},{"@type":"Offer","price":"9","priceCurrency":"EUR","name":"Pro","description":"5,000 PDFs per month, priority support","billingIncrement":"P1M"}]}
+{"@context":"https://schema.org","@type":"WebApplication","name":"DocFast","url":"https://docfast.dev","browserRequirements":"Requires JavaScript. Requires HTML5.","applicationCategory":"DeveloperApplication","operatingSystem":"All","offers":[{"@type":"Offer","price":"9","priceCurrency":"EUR","name":"Pro","description":"5,000 PDFs per month, priority support","billingIncrement":"P1M"}]}
 </script>
 <link rel="icon" href="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'><text y='.9em' font-size='90'>⚡</text></svg>">
 <style>
@@ -262,6 +262,10 @@ html, body {
 #emailChangeResult.active { display: block; }
 #emailChangeVerify.active { display: block; }
 
+/* Demo playground */
+.demo-playground { padding: 80px 0; }
+.demo-playground textarea:focus { outline: 2px solid var(--accent); outline-offset: -2px; }
+
 /* Focus-visible for accessibility */
 .btn:focus-visible, a:focus-visible, input:focus-visible, button:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
 /* Skip to content */
@@ -293,10 +297,10 @@ html, body {
     <h1>HTML to <span class="gradient">PDF</span><br>in one API call</h1>
     <p>Convert HTML, Markdown, or URLs to pixel-perfect PDFs. Built-in templates for invoices &amp; receipts. No headless browser headaches.</p>
     <div class="hero-actions">
-      <button class="btn btn-primary" id="btn-signup" aria-label="Get free API key">Get Free API Key →</button>
-      <a href="/docs" class="btn btn-secondary">Read the Docs</a>
+      <a href="#demo" class="btn btn-primary" id="btn-try-demo">Try Demo →</a>
+      <button class="btn btn-secondary" id="btn-checkout-hero" aria-label="Get Pro API key">Get Pro API Key — €9/mo</button>
     </div>
-    <p style="margin-top:16px;color:var(--muted);font-size:0.9rem;">Already have an account? <a href="#" class="open-recover" style="color:var(--accent);">Lost your API key? Recover it →</a></p>
+    <p style="margin-top:16px;color:var(--muted);font-size:0.9rem;">No signup needed for demo • <a href="#" class="open-recover" style="color:var(--accent);">Lost your API key? Recover it →</a></p>
 
     <div class="code-section">
       <div class="code-header">
@@ -392,28 +396,29 @@ html, body {
 <section class="pricing" id="pricing">
   <div class="container">
     <h2 class="section-title">Simple, transparent pricing</h2>
-    <p class="section-sub">Start free. Upgrade when you're ready. No surprise charges.</p>
-    <div class="pricing-grid">
+    <p class="section-sub">Try instantly with the demo. Go Pro when you're ready.</p>
+    <div class="pricing-grid" style="grid-template-columns:1fr 1fr;max-width:700px;">
       <div class="price-card">
-        <div class="price-name">Free</div>
-        <div class="price-amount">€0<span> /mo</span></div>
-        <div class="price-desc">Perfect for side projects and testing</div>
+        <div class="price-name">Demo</div>
+        <div class="price-amount" style="font-size:2rem;">Free<span></span></div>
+        <div class="price-desc">Try it out — no signup needed</div>
         <ul class="price-features">
-          <li>100 PDFs per month</li>
-          <li>All conversion endpoints</li>
-          <li>All templates included</li>
-          <li>Rate limiting: 10 req/min</li>
+          <li>5 PDFs per hour</li>
+          <li>HTML &amp; Markdown to PDF</li>
+          <li>Watermarked output</li>
+          <li>No API key required</li>
         </ul>
-        <button class="btn btn-secondary" style="width:100%" id="btn-signup-2" aria-label="Get free API key">Get Free API Key</button>
+        <a href="#demo" class="btn btn-secondary" style="width:100%">Try Demo ↓</a>
       </div>
       <div class="price-card featured">
         <div class="price-name">Pro</div>
         <div class="price-amount">€9<span> /mo</span></div>
         <div class="price-desc">For production apps and businesses</div>
         <ul class="price-features">
-<li>5,000 PDFs per month</li>
+          <li>5,000 PDFs per month</li>
           <li>All conversion endpoints</li>
           <li>All templates included</li>
+          <li>Clean PDFs — no watermark</li>
           <li>Priority support (<a href="mailto:support@docfast.dev">support@docfast.dev</a>)</li>
         </ul>
         <button class="btn btn-primary" style="width:100%" id="btn-checkout" aria-label="Get started with Pro plan">Get Started →</button>
@@ -422,6 +427,36 @@ html, body {
   </div>
 </section>
 
+<section class="demo-playground" id="demo">
+  <div class="container">
+    <h2 class="section-title">Try it now</h2>
+    <p class="section-sub">Generate a PDF right here — no signup, no API key. 5 free demos per hour.</p>
+    <div style="max-width:700px;margin:0 auto;">
+      <div class="code-header">
+        <div class="code-dots" aria-hidden="true"><span></span><span></span><span></span></div>
+        <span class="code-label">HTML → PDF playground</span>
+      </div>
+      <textarea id="demoHtml" aria-label="HTML input for demo PDF generation" style="width:100%;min-height:180px;padding:20px;background:var(--card);border:1px solid var(--border);border-top:none;color:var(--fg);font-family:'SF Mono','Fira Code',monospace;font-size:0.85rem;line-height:1.7;resize:vertical;border-radius:0;" spellcheck="false"><h1 style="color:#34d399;font-family:sans-serif;">Hello from DocFast!</h1>
+<p style="font-family:sans-serif;font-size:18px;color:#333;">This is a demo PDF generated via the DocFast API.</p>
+<ul style="font-family:sans-serif;color:#555;">
+  <li>HTML &amp; Markdown to PDF</li>
+  <li>Sub-second generation</li>
+  <li>EU hosted, GDPR compliant</li>
+</ul></textarea>
+      <div style="display:flex;gap:12px;align-items:center;margin-top:16px;flex-wrap:wrap;">
+        <button class="btn btn-primary" id="demoGenerateBtn" aria-label="Generate demo PDF">Generate PDF →</button>
+        <span id="demoStatus" style="color:var(--muted);font-size:0.85rem;"></span>
+      </div>
+      <div id="demoResult" style="display:none;margin-top:16px;padding:16px;background:var(--card);border:1px solid var(--accent);border-radius:var(--radius);text-align:center;">
+        <p style="margin-bottom:12px;color:var(--fg);">✅ PDF generated!</p>
+        <a id="demoDownload" href="#" download="demo.pdf" class="btn btn-primary" style="display:inline-flex;">Download PDF ↓</a>
+        <p style="margin-top:12px;color:var(--muted);font-size:0.8rem;">Demo PDFs include a small watermark. <a href="#pricing">Upgrade to Pro</a> for clean output.</p>
+      </div>
+      <div id="demoError" style="display:none;margin-top:16px;padding:14px;background:rgba(248,113,113,0.06);border:1px solid rgba(248,113,113,0.15);border-radius:var(--radius);color:#f87171;font-size:0.9rem;"></div>
+    </div>
+  </div>
+</section>
+
 </main>
 
 <footer aria-label="Footer">
@@ -439,50 +474,6 @@ html, body {
   </div>
 </footer>
 
-<!-- Signup Modal -->
-<div class="modal-overlay" id="signupModal" role="dialog" aria-modal="true" aria-label="Sign up for API key">
-  <div class="modal">
-    <button class="close" id="btn-close-signup" aria-label="Close dialog">&times;</button>
-
-    <div id="signupInitial" class="active">
-      <h2>Get your free API key</h2>
-      <p>Enter your email to get started. No credit card required.</p>
-      <div class="signup-error" id="signupError"></div>
-      <input type="email" id="signupEmail" aria-label="Email address" placeholder="your.email@example.com" style="width:100%;padding:12px;border:1px solid var(--border);background:var(--bg);color:var(--fg);border-radius:8px;font-size:0.9rem;margin-bottom:16px;" required>
-      <button class="btn btn-primary" style="width:100%" id="signupBtn" aria-label="Generate API key">Generate API Key →</button>
-      <p style="margin-top:16px;color:var(--muted);font-size:0.8rem;text-align:center;">100 free PDFs/month • All endpoints included<br><a href="#" class="open-recover" style="color:var(--muted)">Lost your API key? Recover it →</a></p>
-    </div>
-
-    <div id="signupLoading">
-      <div class="spinner"></div>
-      <p style="color:var(--muted);margin:0">Generating your API key…</p>
-    </div>
-
-    <div id="signupVerify">
-      <h2>Enter verification code</h2>
-      <p>We sent a 6-digit code to <strong id="verifyEmailDisplay"></strong></p>
-      <div class="signup-error" id="verifyError"></div>
-      <input type="text" id="verifyCode" aria-label="Verification code" placeholder="123456" maxlength="6" pattern="[0-9]{6}" inputmode="numeric" style="width:100%;padding:14px;border:1px solid var(--border);background:var(--bg);color:var(--fg);border-radius:8px;font-size:1.4rem;letter-spacing:0.3em;text-align:center;margin-bottom:16px;font-family:monospace;" required>
-      <button class="btn btn-primary" style="width:100%" id="verifyBtn" aria-label="Verify code">Verify →</button>
-      <p style="margin-top:16px;color:var(--muted);font-size:0.8rem;text-align:center;">Code expires in 15 minutes</p>
-    </div>
-
-    <div id="signupResult" aria-live="polite">
-      <h2>🚀 Your API key is ready!</h2>
-      <div class="warning-box">
-        <span class="icon">⚠️</span>
-        <span>Save your API key securely. Lost it? <a href="#" class="open-recover" style="color:#fbbf24">Recover via email</a></span>
-      </div>
-      <div style="background:var(--bg);border:1px solid var(--accent);border-radius:8px;padding:14px;font-family:monospace;font-size:0.82rem;word-break:break-all;margin:16px 0;position:relative;">
-        <span id="apiKeyText"></span>
-        <button onclick="copyKey()" id="copyBtn" aria-label="Copy API key" style="position:absolute;top:8px;right:8px;background:var(--accent);color:var(--bg);border:none;border-radius:4px;padding:4px 12px;cursor:pointer;font-size:0.8rem;">Copy</button>
-      </div>
-      <p style="margin-top:20px;color:var(--muted);font-size:0.9rem;">100 free PDFs/month • <a href="/docs">Read the docs →</a></p>
-    </div>
-  </div>
-</div>
-
-
 <!-- Recovery Modal -->
 <div class="modal-overlay" id="recoverModal" role="dialog" aria-modal="true" aria-label="Recover API key">
   <div class="modal">