Add gnommo.sh wrapper and fix slide/scaling issues

gnommo.sh:
- Bash wrapper for easy CLI usage
- Commands: validate, transcribe, align, render, all
- `gnommo.sh -p video1 all` runs full pipeline

Slide scaling:
- Slides now scale to full frame (1920x1080)
- Transparent areas show through to layers below
- Positioned at 0,0 for full overlay

targetheight percentage:
- Supports percentage values like "100%"
- Calculates actual height from frame resolution
- "100%" on 1080p = 1080px height

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

gnommo/renderer.py

@@ -128,7 +128,11 @@ def build_filter_complex(
 
     # Scale and position talking head
     th_config = plan.config.talking_head
-    th_height = th_config.target_height if th_config.target_height > 0 else height
+    if th_config.target_height > 0:
+        th_height = th_config.target_height
+    else:
+        # Percentage-based: calculate from frame height
+        th_height = int(height * th_config.target_height_percent)
 
     filters.append(
         f"[{talking_head_idx}:v]scale=-1:{th_height}[head]"
@@ -142,24 +146,24 @@ def build_filter_complex(
     current_label = "base"
 
     # Add slide overlays with time-based enable
+    # Slides are scaled to full frame - transparency shows layers below
     for i, event in enumerate(plan.slide_events):
         slide_idx = slide_start_idx + slide_inputs.index(event.slide_id)
-        layout = SLIDE_LAYOUTS.get(event.slide_def.type, SLIDE_LAYOUTS["square"])
 
-        # Scale slide to fit layout while preserving aspect ratio
+        # Scale slide to full frame size (transparent areas show through)
         slide_label = f"s{i}"
         filters.append(
-            f"[{slide_idx}:v]scale={layout['width']}:{layout['height']}:"
-            f"force_original_aspect_ratio=decrease[{slide_label}]"
+            f"[{slide_idx}:v]scale={width}:{height}:"
+            f"force_original_aspect_ratio=decrease,pad={width}:{height}:(ow-iw)/2:(oh-ih)/2:color=0x00000000[{slide_label}]"
         )
 
-        # Overlay with time-based enable
+        # Overlay at 0,0 (full frame) with time-based enable
         next_label = f"v{i}" if i < len(plan.slide_events) - 1 else "vout"
         enable_expr = f"between(t,{event.start_time:.3f},{event.end_time:.3f})"
 
         filters.append(
             f"[{current_label}][{slide_label}]overlay="
-            f"x={layout['x']}:y={layout['y']}:"
+            f"x=0:y=0:"
             f"enable='{enable_expr}'[{next_label}]"
         )