Add paid-service captures, aggregator attribution, and provenance vetoes

Collect provider samples from Higgsfield, Runway and Dreamina plus Google
Photos, Gemini, Grok and YouTube re-encodes into data/captures/2026-09 with
a hash-checked manifest, and use them to fix attribution and false positives:

- Attribute aggregator outputs: Higgsfield job metadata, Dreamina's
  re-signed manifests, Runway's own C2PA signer, TC260 video producers.
- Veto any visible video mark when a valid C2PA claim names another vendor
  (a Gemini Omni clip read as Sora on steam), and gate Kling and Hailuo
  matches on edge, anchor and white-label evidence.
- Veto the Gemini sparkle when trusted provenance names another vendor.
- Report SynthID as present for Google Photos AI edits: Google's checker
  found it on all four measured edits, though manifests record no action.
- Add Vidu video and Wan image marks, TC260 audio placements, and record
  the AIGC key in metadata records.
- Document the research sweep, the Dreamina badge decision, and verified
  Google statements on SynthID in Photos.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/render_visible_examples.py

@@ -283,6 +283,14 @@ def _video_mark_frame(key: str, w: int, h: int) -> np.ndarray:
         tmpl, scale, x, y = templates["dola"], 0.036, int(w * 0.70), int(h * 0.88)
     elif key == "hailuo":
         tmpl, scale, x, y = templates["hailuo"], 0.052, int(w * 0.34), int(h * 0.82)
+    elif key == "vidu":
+        # Logo plus wordmark bottom-right, at the measured 1080p geometry: 4.6% of
+        # the short side tall, ~3% off the right and bottom edges.
+        tmpl = templates["vidu"]
+        th = max(8, round(short * 0.046))
+        tw = max(1, round(tmpl.shape[1] * th / tmpl.shape[0]))
+        x, y = w - tw - round(short * 0.029), h - th - round(short * 0.033)
+        return _composite_light(base, cv2.resize(tmpl, (tw, th)).astype(np.float32) / 255.0, x, y, 250)
     elif key == "kling":
         # The FULL mark: swirl logo left of the text run, flush against the
         # bottom-right EDGE. The font arm is edge-gated (region must reach