fix(13-01): upgrade to gpt-4o, remove checkboxes, clamp AI coords to page bounds

- gpt-4o-mini replaced with gpt-4o for better placement accuracy
- checkbox removed from schema enum and filtered in loop (positions are input-dependent)
- y coordinate clamped to [0, pageHeight - fieldHeight] to prevent fields rendering
  outside the PDF canvas when AI returns yPct near 100%

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

teressa-copeland-homes/src/lib/ai/field-placement.ts

@@ -43,7 +43,10 @@ export function aiCoordsToPagePdfSpace(
   const x = screenX;
   // PDF y = distance from BOTTOM. screenY is from top, so flip:
   // pdfY = pageHeight - screenY - fieldHeight  (bottom edge of field)
-  const y = pageHeight - screenY - fieldHeight;
+  // Clamp to [0, pageHeight - fieldHeight] so AI coords near page edges
+  // don't produce negative y values that render outside the canvas.
+  const rawY = pageHeight - screenY - fieldHeight;
+  const y = Math.max(0, Math.min(rawY, pageHeight - fieldHeight));
 
   return { x, y, width: fieldWidth, height: fieldHeight };
 }
@@ -60,7 +63,7 @@ const FIELD_PLACEMENT_SCHEMA = {
         type: 'object',
         properties: {
           page:         { type: 'integer' },
-          fieldType:    { type: 'string', enum: ['text', 'checkbox', 'initials', 'date', 'client-signature', 'agent-signature', 'agent-initials'] },
+          fieldType:    { type: 'string', enum: ['text', 'initials', 'date', 'client-signature', 'agent-signature', 'agent-initials'] },
           xPct:         { type: 'number' },
           yPct:         { type: 'number' },   // % from page TOP (AI top-left origin)
           widthPct:     { type: 'number' },
@@ -102,16 +105,18 @@ export async function classifyFieldsWithAI(
     .join('\n\n');
 
   const response = await openai.chat.completions.create({
-    model: 'gpt-4o-mini',
+    model: 'gpt-4o',
     messages: [
       {
         role: 'system',
         content: `You are a real estate document form field extractor.
 Given extracted text from a PDF page (with context about page number and dimensions),
-identify where signature, text, checkbox, initials, and date fields should be placed.
+identify where signature, initials, text, and date fields should be placed.
 Return fields as percentage positions (0-100) from the TOP-LEFT of the page.
-Use these field types: text (for typed values), checkbox, initials, date, client-signature, agent-signature, agent-initials.
+Use these field types: text (for typed values), initials, date, client-signature, agent-signature, agent-initials.
-For text fields that match the client profile, set prefillValue to the known value. Otherwise use empty string.`,
+Only place fields where the document clearly requires them — prefer fewer, high-confidence placements.
+For text fields that match the client name or property address, set prefillValue to the known value. Otherwise use empty string.
+Do NOT place checkbox fields.`,
       },
       {
         role: 'user',
@@ -135,16 +140,17 @@ For text fields that match the client profile, set prefillValue to the known val
   const textFillData: Record<string, string> = {};
 
   for (const aiField of raw.fields) {
+    // Never place checkboxes — positions depend on user input and can't be AI-determined
+    if (aiField.fieldType === 'checkbox') continue;
+
     const pageInfo = pageTexts.find((p) => p.page === aiField.page);
     const pageWidth  = pageInfo?.width  ?? 612;  // fallback: US Letter
     const pageHeight = pageInfo?.height ?? 792;
 
     const { x, y } = aiCoordsToPagePdfSpace(aiField, pageWidth, pageHeight);
 
-    // Use standard sizes regardless of AI width/height — consistent with FieldPlacer defaults
+    const width  = 144;  // pts: 2 inches
-    const isCheckbox = aiField.fieldType === 'checkbox';
+    const height = 36;   // pts: 0.5 inches
-    const width  = isCheckbox ? 24 : 144;  // pts: checkbox=24x24, others=144x36
-    const height = isCheckbox ? 24 : 36;
 
     const id = crypto.randomUUID();