Add LLM OCR engine via OpenCode Go + mimo-v2-omni

Adds optional LLM-based OCR as an alternative to Tesseract for reading
machine IDs from photos.

Backend (server.py):
- New run_ocr_llm() function calls OpenCode Go API (mimo-v2-omni model)
- Auto-falls back to Tesseract if API key missing or call fails
- Endpoints /api/analyze and /api/bulk-process accept ?ocr_engine=llm
  query param (default: tesseract) and ?ocr_model for model override
- Configurable via env vars: OPENCODE_GO_API_KEY, LLM_OCR_MODEL
- Requires User-Agent: Hermes-Agent/1.0 header for OpenCode Go API

Frontend (static/index.html):
- Toggle checkbox 'Use LLM OCR' in the UI
- OCR engine badge shown in results (llm vs tesseract + model name)
- getOcrParams() helper appends ?ocr_engine=llm to API calls

Infrastructure:
- .gitignore for uploads/ directory

Closes: #2

static/index.html

@@ -187,6 +187,20 @@
     margin-top: 6px;
   }
 
+  /* OCR engine toggle */
+  .ocr-toggle {
+    display: flex; align-items: center; gap: 8px; margin-bottom: 8px;
+    font-size: 12px; color: var(--text2);
+  }
+  .ocr-toggle label { display: flex; align-items: center; gap: 4px; cursor: pointer; }
+  .ocr-toggle input[type="checkbox"] { accent-color: var(--accent); }
+  .engine-badge {
+    font-size: 10px; padding: 2px 8px; border-radius: 10px; font-weight: 600;
+    background: var(--card2); color: var(--text2); display: inline-block; margin-left: 4px;
+  }
+  .engine-badge.llm { background: var(--accent); color: #fff; }
+  .engine-badge.tesseract { background: var(--card2); color: var(--text2); }
+
   /* Bulk results */
   #mapContainer { height: 250px; border-radius: var(--radius-sm); margin-bottom: 10px; display: none; }
   .bulk-card {
@@ -263,6 +277,14 @@
   <div id="serverResults"></div>
 </div>
 
+<!-- OCR engine toggle -->
+<div class="ocr-toggle" style="margin-bottom:4px;">
+  <label>
+    <input type="checkbox" id="ocrLlmToggle" onchange="onOcrToggle()">
+    🧠 Use LLM OCR (<code id="ocrModelLabel">mimo-v2-omni</code>)
+  </label>
+</div>
+
 <!-- Bulk process button -->
 <button class="btn btn-primary" id="bulkBtn" style="display:none;margin-top:12px;" onclick="startBulkProcess()">
   🔍 Bulk Process GPS Photos
@@ -440,7 +462,7 @@ async function uploadSelected() {
   fd.append('file', file, file.name || 'photo.jpg');
 
   try {
-    const resp = await fetch('/api/analyze', { method: 'POST', body: fd });
+    const resp = await fetch('/api/analyze' + getOcrParams(), { method: 'POST', body: fd });
     const data = await resp.json();
 
     let html = '';
@@ -465,21 +487,20 @@ async function uploadSelected() {
 
     // OCR
     const ocr = data.ocr;
-    if (ocr.available) {
-      html += '<div style="margin-top:10px;font-weight:600;">🔤 OCR:</div>';
-      if (ocr.raw_text) {
-        html += '<div class="ocr-text">' + esc(ocr.raw_text) + '</div>';
-      }
-      if (ocr.match_5dash6) {
-        const mid = ocr.match_5dash6.replace(/[^0-9]/g,'').slice(-5);
-        html += '<div style="margin-top:4px;color:var(--green);">✅ Matched: <strong>' + esc(ocr.match_5dash6) + '</strong> → machine ID: ' + mid + '</div>';
-        // Auto-lookup
-        lookupAsset(mid);
-      } else if (ocr.match_5plus) {
-        html += '<div style="margin-top:4px;color:var(--amber);">⚠️ Digits: <strong>' + esc(ocr.match_5plus) + '</strong> (no 5-6 pattern)</div>';
-      } else {
-        html += '<div style="margin-top:4px;color:var(--text3);">No machine ID found in image</div>';
-      }
+    const engineCls = ocr.engine === 'llm' ? 'llm' : 'tesseract';
+    html += '<div style="margin-top:10px;font-weight:600;">🔤 OCR <span class="engine-badge ' + engineCls + '">' + esc(ocr.engine || 'tesseract') + (ocr.llm_model ? ' ' + ocr.llm_model : '') + '</span></div>';
+    if (ocr.raw_text) {
+      html += '<div class="ocr-text">' + esc(ocr.raw_text) + '</div>';
+    }
+    if (ocr.match_5dash6) {
+      const mid = ocr.match_5dash6.replace(/[^0-9]/g,'').slice(-5);
+      html += '<div style="margin-top:4px;color:var(--green);">✅ Matched: <strong>' + esc(ocr.match_5dash6) + '</strong> → machine ID: ' + mid + '</div>';
+      // Auto-lookup
+      lookupAsset(mid);
+    } else if (ocr.match_5plus) {
+      html += '<div style="margin-top:4px;color:var(--amber);">⚠️ Digits: <strong>' + esc(ocr.match_5plus) + '</strong> (no 5-6 pattern)</div>';
+    } else {
+      html += '<div style="margin-top:4px;color:var(--text3);">No machine ID found in image</div>';
     }
 
     div.innerHTML = html;
@@ -540,7 +561,7 @@ async function startBulkProcess() {
   gpsPhotos.forEach(p => fd.append('files', p.file, p.file.name || 'photo.jpg'));
 
   try {
-    const resp = await fetch('/api/bulk-process', { method: 'POST', body: fd });
+    const resp = await fetch('/api/bulk-process' + getOcrParams(), { method: 'POST', body: fd });
     const data = await resp.json();
 
     // Merge thumbnails back into results
@@ -753,8 +774,13 @@ function esc(s) {
   return d.innerHTML;
 }
 
+function getOcrParams() {
+  const useLlm = document.getElementById('ocrLlmToggle').checked;
+  if (!useLlm) return '';
+  return '?ocr_engine=llm';
+}
+
 function formatSize(bytes) {
-  if (bytes < 1024) return bytes + ' B';
   if (bytes < 1048576) return (bytes / 1024).toFixed(1) + ' KB';
   return (bytes / 1048576).toFixed(1) + ' MB';
 }