feat(06-03): signing page — server component, PDF viewer, field overlays, progress bar

- page.tsx: server component validates JWT + one-time-use before rendering any UI
- Three error states (expired/used/invalid) show static pages with no canvas
- SigningPageClientWrapper: dynamic import (ssr:false) for react-pdf browser requirement
- SigningPageClient: full-scroll PDF viewer with pulsing blue field overlays
- Field overlay coordinates convert PDF user-space (bottom-left) to screen (top-left)
- SigningProgressBar: sticky bottom bar with X/Y count + jump-to-next + submit button
- api/sign/[token]/pdf: token-authenticated PDF streaming route (no agent auth)

teressa-copeland-homes/src/app/sign/[token]/_components/SigningProgressBar.tsx

@@ -0,0 +1,76 @@
+'use client';
+
+interface SigningProgressBarProps {
+  total: number;
+  signed: number;
+  onJumpToNext: () => void;
+  onSubmit: () => void;
+  submitting: boolean;
+}
+
+export function SigningProgressBar({
+  total,
+  signed,
+  onJumpToNext,
+  onSubmit,
+  submitting,
+}: SigningProgressBarProps) {
+  const allSigned = signed >= total;
+  return (
+    <div
+      style={{
+        position: 'fixed',
+        bottom: 0,
+        left: 0,
+        right: 0,
+        zIndex: 50,
+        backgroundColor: '#1B2B4B',
+        color: '#fff',
+        display: 'flex',
+        alignItems: 'center',
+        justifyContent: 'space-between',
+        padding: '12px 24px',
+        boxShadow: '0 -2px 8px rgba(0,0,0,0.15)',
+      }}
+    >
+      <span style={{ fontSize: '15px' }}>
+        {signed} of {total} signature{total !== 1 ? 's' : ''} complete
+      </span>
+      <div style={{ display: 'flex', gap: '12px' }}>
+        {!allSigned && (
+          <button
+            onClick={onJumpToNext}
+            style={{
+              backgroundColor: 'transparent',
+              border: '1px solid #C9A84C',
+              color: '#C9A84C',
+              padding: '8px 18px',
+              borderRadius: '4px',
+              cursor: 'pointer',
+              fontSize: '14px',
+            }}
+          >
+            Jump to Next
+          </button>
+        )}
+        <button
+          onClick={onSubmit}
+          disabled={!allSigned || submitting}
+          style={{
+            backgroundColor: allSigned ? '#C9A84C' : '#555',
+            color: '#fff',
+            border: 'none',
+            padding: '8px 22px',
+            borderRadius: '4px',
+            cursor: allSigned ? 'pointer' : 'not-allowed',
+            fontSize: '14px',
+            fontWeight: 'bold',
+            opacity: submitting ? 0.7 : 1,
+          }}
+        >
+          {submitting ? 'Submitting...' : 'Submit Signature'}
+        </button>
+      </div>
+    </div>
+  );
+}