fix: separate recipe preview image from task images

Recipe image_path is now used as preview thumbnail only. Removed
auto-creation of "Technical Drawing" task from recipe upload, and
removed recipe image strip from task_execute view. Each task displays
its own file_path independently.

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

server/services/recipe_service.py

@@ -149,22 +149,6 @@ async def create_recipe(
     db.add(version)
     await db.flush()
 
-    # Create initial task with technical drawing if file was uploaded
-    if data.file_path:
-        initial_task = RecipeTask(
-            version_id=version.id,
-            order_index=0,
-            title="Technical Drawing",
-            file_path=data.file_path,
-            file_type=data.file_type or (
-                "pdf" if data.file_path.lower().endswith(".pdf")
-                else "image"
-            ),
-            annotations_json=data.annotations_json,
-        )
-        db.add(initial_task)
-        await db.flush()
-
     await _write_audit(
         db,
         recipe_id=recipe.id,