feat(refactor/phase2): pipeline modularity + dead code removal

Phase 2.3 — Fix render cancellation (real Celery task ID):
  - orders.py cancel endpoints: read celery_task_id from render_job_doc
    instead of synthetic "render-{line_id}" which was a no-op
  - render_order_line_still_task: creates RenderJobDocument at task start,
    stores self.request.id as celery_task_id, writes step-level state
    (RESOLVE_STEP_PATH → BLENDER_STILL) back to order_lines.render_job_doc

Phase 3.1 — Remove Pillow overlay dead code:
  - blender_render.py: deleted 55-line Pillow post-processing block
    (lines 798-851, green bar + model name label)
  - transparent_bg=True is always passed; the else branch was unreachable
  - Removed mention from script docstring

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

render-worker/scripts/blender_render.py

@@ -14,7 +14,6 @@ Features:
 - Isometric-style angle (elevation 28°, azimuth 40°).
 - Dynamic clip planes.
 - Standard (non-Filmic) colour management → no grey tint.
-- Schaeffler green top bar + model name label via Pillow post-processing.
 """
 import sys
 import os
@@ -795,59 +794,4 @@ sys.stdout.flush()
 bpy.ops.render.render(write_still=True)
 print("[blender_render] render done.", flush=True)
 
-# ── Pillow post-processing: green bar + model name label ─────────────────────
-# Skip overlay for transparent renders to keep clean alpha channel
-if transparent_bg:
-    print("[blender_render] Transparent mode — skipping Pillow overlay.")
-else:
-    try:
-        from PIL import Image, ImageDraw, ImageFont
-
-        img  = Image.open(output_path).convert("RGBA")
-        draw = ImageDraw.Draw(img)
-        W, H = img.size
-
-        # Schaeffler green top bar
-        bar_h = max(8, H // 32)
-        draw.rectangle([0, 0, W - 1, bar_h - 1], fill=(0, 137, 61, 255))
-
-        # Model name strip at bottom
-        model_name = os.path.splitext(os.path.basename(glb_path))[0]
-        label_h    = max(20, H // 20)
-        img.alpha_composite(
-            Image.new("RGBA", (W, label_h), (30, 30, 30, 180)),
-            dest=(0, H - label_h),
-        )
-
-        font_size = max(10, label_h - 6)
-        font = None
-        for fp in [
-            "/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf",
-            "/usr/share/fonts/truetype/liberation/LiberationSans-Bold.ttf",
-            "/usr/share/fonts/truetype/freefont/FreeSansBold.ttf",
-        ]:
-            if os.path.exists(fp):
-                try:
-                    font = ImageFont.truetype(fp, font_size)
-                    break
-                except Exception:
-                    pass
-        if font is None:
-            font = ImageFont.load_default()
-
-        tb     = draw.textbbox((0, 0), model_name, font=font)
-        text_w = tb[2] - tb[0]
-        draw.text(
-            ((W - text_w) // 2, H - label_h + (label_h - (tb[3] - tb[1])) // 2),
-            model_name, font=font, fill=(255, 255, 255, 255),
-        )
-
-        img.convert("RGB").save(output_path, format="PNG")
-        print(f"[blender_render] Pillow overlay applied.")
-
-    except ImportError:
-        print("[blender_render] Pillow not in Blender Python – skipping overlay.")
-    except Exception as exc:
-        print(f"[blender_render] Pillow overlay failed (non-fatal): {exc}")
-
 print("[blender_render] Done.")