Fix corrupt trend pptx when score trends upward

The Score Trajectory slide drew connecting lines between data points
with width = p2.x - p1.x and height = p2.y - p1.y. When the org's score
improves between periods, y decreases (smaller y means higher up the
chart), so the height was negative.

Some Office versions silently corrupt the pptx when a shape has
negative dimensions: writeFile reports success and the file looks
intact on disk, but the slide rels reference an unwritten slide and
the file fails to open ("file or directory is corrupted and
unreadable"). Reproduced with two- and three-period histories that
trend upward.

Always pass positive width/height and use flipV when the trajectory
goes up. Result: 3-month upward histories now render correctly across
all three trend slides.

Also refresh the committed Slide2 screenshot to match the deck the
generator now produces (rich tier narrative + 3 cards + focus and
strengths).

Author: InfoSecJay

docs/screenshots/Slide2.JPG

@@ -273,16 +273,23 @@ if (!hasMultiple) {
     return { x, y, score: entry.overallScore || 0, date: entry.date, tier: entry.achievedTier };
   });
 
-  // Connect points with lines
+  // Connect points with lines.
+  // PowerPoint chokes on shapes with negative width/height (the file opens
+  // but every reader since Office 2016 reports it as corrupted). When the
+  // trend is upward — score increasing means y decreasing — the naive
+  // (p2 - p1) delta goes negative, so we always draw with positive
+  // dimensions and use flipV to mirror the line vertically when needed.
   for (let i = 1; i < points.length; i++) {
     const p1 = points[i - 1];
     const p2 = points[i];
-    // Use a thin rectangle as a line approximation (pptxgenjs LINE is tricky for angled)
+    const w = p2.x - p1.x;
+    const dy = p2.y - p1.y;
     s1.addShape(pres.shapes.LINE, {
       x: p1.x,
-      y: p1.y,
-      w: p2.x - p1.x,
-      h: p2.y - p1.y,
+      y: dy >= 0 ? p1.y : p2.y,
+      w: w,
+      h: Math.abs(dy),
+      flipV: dy < 0,
       line: { color: C.cyan, width: 2.5 },
     });
   }